From 221161ceccd224f9b0f871426ddd656f358a2f5b Mon Sep 17 00:00:00 2001 From: Michael Ficarra Date: Tue, 4 Oct 2011 22:24:36 -0400 Subject: [PATCH 01/29] better isXXX checks; the current tests have too many false positives --- test/objects.js | 5 +++-- underscore.js | 17 +++++++++-------- 2 files changed, 12 insertions(+), 10 deletions(-) diff --git a/test/objects.js b/test/objects.js index e05c0ddc5..0e1f3e4f3 100644 --- a/test/objects.js +++ b/test/objects.js @@ -383,14 +383,15 @@ $(document).ready(function() { ok(!_.isNumber(arguments), 'the arguments object is not a number'); ok(!_.isNumber(undefined), 'undefined is not a number'); ok(_.isNumber(3 * 4 - 7 / 10), 'but numbers are'); - ok(!_.isNumber(NaN), 'NaN is not a number'); + ok(_.isNumber(NaN), 'NaN *is* a number'); ok(_.isNumber(Infinity), 'Infinity is a number'); ok(_.isNumber(iNumber), 'even from another frame'); + ok(!_.isNumber('1'), 'numeric strings are not numbers'); }); test("objects: isBoolean", function() { ok(!_.isBoolean(2), 'a number is not a boolean'); - ok(!_.isBoolean("string"), 'a string is not a boolean'); + ok(!_.isBoolean("string"), 'a string is not a boolean'); ok(!_.isBoolean("false"), 'the string "false" is not a boolean'); ok(!_.isBoolean("true"), 'the string "true" is not a boolean'); ok(!_.isBoolean(arguments), 'the arguments object is not a boolean'); diff --git a/underscore.js b/underscore.js index 0db66d0b6..182070eb3 100644 --- a/underscore.js +++ b/underscore.js @@ -714,7 +714,8 @@ return eq(a, b, []); }; - // Is a given array or object empty? + // Is a given array, string, or object empty? + // An "empty" object has no enumerable own-properties. _.isEmpty = function(obj) { if (_.isArray(obj) || _.isString(obj)) return obj.length === 0; for (var key in obj) if (hasOwnProperty.call(obj, key)) return false; @@ -729,7 +730,7 @@ // Is a given value an array? // Delegates to ECMA5's native Array.isArray _.isArray = nativeIsArray || function(obj) { - return toString.call(obj) === '[object Array]'; + return toString.call(obj) == '[object Array]'; }; // Is a given variable an object? @@ -739,22 +740,22 @@ // Is a given variable an arguments object? _.isArguments = function(obj) { - return !!(obj && hasOwnProperty.call(obj, 'callee')); + return toString.call(obj) == '[object Arguments]' || !!(obj && hasOwnProperty.call(obj, 'callee')); }; // Is a given value a function? _.isFunction = function(obj) { - return !!(obj && obj.constructor && obj.call && obj.apply); + return toString.call(obj) == '[object Function]'; }; // Is a given value a string? _.isString = function(obj) { - return !!(obj === '' || (obj && obj.charCodeAt && obj.substr)); + return toString.call(obj) == '[object String]'; }; // Is a given value a number? _.isNumber = function(obj) { - return !!(obj === 0 || (obj && obj.toExponential && obj.toFixed)); + return toString.call(obj) == '[object Number]'; }; // Is the given value `NaN`? `NaN` happens to be the only value in JavaScript @@ -770,12 +771,12 @@ // Is a given value a date? _.isDate = function(obj) { - return !!(obj && obj.getTimezoneOffset && obj.setUTCFullYear); + return toString.call(obj) == '[object Date]'; }; // Is the given value a regular expression? _.isRegExp = function(obj) { - return !!(obj && obj.test && obj.exec && (obj.ignoreCase || obj.ignoreCase === false)); + return toString.call(obj) == '[object RegExp]'; }; // Is a given value equal to null? From f2a64227fdd72a5ad8aaee03e1cab81f13ae130e Mon Sep 17 00:00:00 2001 From: Kevin Malakoff Date: Thu, 6 Oct 2011 15:50:51 +0200 Subject: [PATCH 02/29] Reimplemented _.isEqual tests and patch in a fresh branch. --- test/objects.js | 52 +++++++++++++++++++++++++++++++++++++++++++++++++ underscore.js | 13 +++++++++---- 2 files changed, 61 insertions(+), 4 deletions(-) diff --git a/test/objects.js b/test/objects.js index e05c0ddc5..c131d920b 100644 --- a/test/objects.js +++ b/test/objects.js @@ -295,6 +295,58 @@ $(document).ready(function() { ok(_.isEqual(isEqualObjClone, isEqualObj), 'Commutative equality is implemented for objects with custom `isEqual` methods'); ok(!_.isEqual(isEqualObj, {}), 'Objects that do not implement equivalent `isEqual` methods are not equal'); ok(!_.isEqual({}, isEqualObj), 'Commutative equality is implemented for objects with different `isEqual` methods'); + + // Custom `isEqual` methods - comparing different types + LocalizedString = (function() { + function LocalizedString(id) { this.id = id; this.string = (this.id===10)? 'Bonjour': ''; } + LocalizedString.prototype.isEqual = function(that) { + if (_.isString(that)) return this.string == that; + else if (that instanceof LocalizedString) return this.id == that.id; + return false; + }; + return LocalizedString; + })(); + var localized_string1 = new LocalizedString(10), localized_string2 = new LocalizedString(10), localized_string3 = new LocalizedString(11); + ok(_.isEqual(localized_string1, localized_string2), 'comparing same typed instances with same ids'); + ok(!_.isEqual(localized_string1, localized_string3), 'comparing same typed instances with different ids'); + ok(_.isEqual(localized_string1, 'Bonjour'), 'comparing different typed instances with same values'); + ok(_.isEqual('Bonjour', localized_string1), 'comparing different typed instances with same values'); + ok(!_.isEqual('Bonjour', localized_string3), 'comparing two localized strings with different ids'); + ok(!_.isEqual(localized_string1, 'Au revoir'), 'comparing different typed instances with different values'); + ok(!_.isEqual('Au revoir', localized_string1), 'comparing different typed instances with different values'); + + // Custom `isEqual` methods - comparing with serialized data + Date.prototype.toJSON = function() { + return { + _type:'Date', + year:this.getUTCFullYear(), + month:this.getUTCMonth(), + day:this.getUTCDate(), + hours:this.getUTCHours(), + minutes:this.getUTCMinutes(), + seconds:this.getUTCSeconds() + }; + }; + Date.prototype.isEqual = function(that) { + var this_date_components = this.toJSON(); + var that_date_components = (that instanceof Date) ? that.toJSON() : that; + delete this_date_components['_type']; delete that_date_components['_type'] + return _.isEqual(this_date_components, that_date_components); + }; + + var date = new Date(); + var date_json = { + _type:'Date', + year:date.getUTCFullYear(), + month:date.getUTCMonth(), + day:date.getUTCDate(), + hours:date.getUTCHours(), + minutes:date.getUTCMinutes(), + seconds:date.getUTCSeconds() + }; + + ok(_.isEqual(date_json, date), 'serialized date matches date'); + ok(_.isEqual(date, date_json), 'date matches serialized date'); }); test("objects: isEmpty", function() { diff --git a/underscore.js b/underscore.js index eee91067d..610533673 100644 --- a/underscore.js +++ b/underscore.js @@ -635,7 +635,15 @@ // See the Harmony `egal` proposal: http://wiki.ecmascript.org/doku.php?id=harmony:egal. if (a === b) return a !== 0 || 1 / a == 1 / b; // A strict comparison is necessary because `null == undefined`. - if (a == null) return a === b; + if ((a == null) || (b == null)) return a === b; + // Either one is undefined + if ((a === void 0) || (b === void 0)) return false; + // Unwrap any wrapped objects. + if (a._chain) a = a._wrapped; + if (b._chain) b = b._wrapped; + // One of them implements an isEqual() + if (a.isEqual) return a.isEqual(b); + if (b.isEqual) return b.isEqual(a); // Compare object types. var typeA = typeof a; if (typeA != typeof b) return false; @@ -667,9 +675,6 @@ } // Ensure that both values are objects. if (typeA != 'object') return false; - // Unwrap any wrapped objects. - if (a._chain) a = a._wrapped; - if (b._chain) b = b._wrapped; // Invoke a custom `isEqual` method if one is provided. if (_.isFunction(a.isEqual)) return a.isEqual(b); // Assume equality for cyclic structures. The algorithm for detecting cyclic structures is From 81c9dc2f1fdd324846ddaa0c0fe255be114f91e6 Mon Sep 17 00:00:00 2001 From: Kevin Malakoff Date: Thu, 6 Oct 2011 18:23:42 +0200 Subject: [PATCH 03/29] yuchi spotted duplication --- underscore.js | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/underscore.js b/underscore.js index 610533673..73ffa58ce 100644 --- a/underscore.js +++ b/underscore.js @@ -641,9 +641,9 @@ // Unwrap any wrapped objects. if (a._chain) a = a._wrapped; if (b._chain) b = b._wrapped; - // One of them implements an isEqual() - if (a.isEqual) return a.isEqual(b); - if (b.isEqual) return b.isEqual(a); + // Invoke a custom `isEqual` method if one is provided. + if (_.isFunction(a.isEqual)) return a.isEqual(b); + if (_.isFunction(b.isEqual)) return b.isEqual(a); // Compare object types. var typeA = typeof a; if (typeA != typeof b) return false; @@ -675,8 +675,6 @@ } // Ensure that both values are objects. if (typeA != 'object') return false; - // Invoke a custom `isEqual` method if one is provided. - if (_.isFunction(a.isEqual)) return a.isEqual(b); // Assume equality for cyclic structures. The algorithm for detecting cyclic structures is // adapted from ES 5.1 section 15.12.3, abstract operation `JO`. var length = stack.length; From 69bb2e03fab1dae907a64b275204074e20f165f3 Mon Sep 17 00:00:00 2001 From: Kevin Malakoff Date: Thu, 6 Oct 2011 18:51:24 +0200 Subject: [PATCH 04/29] Reducant check spotted by kitcambridge. --- underscore.js | 2 -- 1 file changed, 2 deletions(-) diff --git a/underscore.js b/underscore.js index 73ffa58ce..d19e26960 100644 --- a/underscore.js +++ b/underscore.js @@ -636,8 +636,6 @@ if (a === b) return a !== 0 || 1 / a == 1 / b; // A strict comparison is necessary because `null == undefined`. if ((a == null) || (b == null)) return a === b; - // Either one is undefined - if ((a === void 0) || (b === void 0)) return false; // Unwrap any wrapped objects. if (a._chain) a = a._wrapped; if (b._chain) b = b._wrapped; From 2085963d190b7d69331a99fb25a93d31d002bd4c Mon Sep 17 00:00:00 2001 From: Jason Davies Date: Sat, 15 Oct 2011 11:09:49 +0100 Subject: [PATCH 05/29] Fix typo. --- index.html | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/index.html b/index.html index ab31da513..f95bf17bd 100644 --- a/index.html +++ b/index.html @@ -776,7 +776,7 @@ _.functions(_); extend_.extend(destination, *sources)
Copy all of the properties in the source objects over to the - destination object. It's in-order, to the last source will override + destination object. It's in-order, so the last source will override properties of the same name in previous arguments. 


From e6381d8ee7c82f838bfcba6cdeccfca924e65041 Mon Sep 17 00:00:00 2001
From: jrburke 
Date: Mon, 17 Oct 2011 17:58:03 -0700
Subject: [PATCH 06/29] Opt in to AMD registration.

---
 underscore.js | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/underscore.js b/underscore.js
index d19e26960..ba9b8aea3 100644
--- a/underscore.js
+++ b/underscore.js
@@ -57,6 +57,19 @@
   } else {
     // Exported as a string, for Closure Compiler "advanced" mode.
     root['_'] = _;
+
+    // Register as a module with AMD. Use a named module since underscore
+    // can be used in optimization schemes that do not understand anonymous
+    // modules, and the if it is used on a page with an AMD loader, a load
+    // error could occur. This work is done in addition to exporting a global
+    // on root since the web page could use an AMD loader to load the module
+    // but still want to use the global reference. Test pages are a good
+    // example.
+    if (typeof define === 'function' && define.amd) {
+      define('underscore', function() {
+        return _;
+      });
+    }
   }
 
   // Current version.

From 0513f60b63f08636dc0908730c7d4334aa322773 Mon Sep 17 00:00:00 2001
From: Tony Lukasavage 
Date: Tue, 18 Oct 2011 11:50:46 -0300
Subject: [PATCH 07/29] add support for CommonJS implementations that do not
 support modules.exports.

---
 underscore.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/underscore.js b/underscore.js
index d19e26960..f09221580 100644
--- a/underscore.js
+++ b/underscore.js
@@ -54,6 +54,8 @@
   if (typeof module !== 'undefined' && module.exports) {
     module.exports = _;
     _._ = _;
+  } else if (exports !== 'undefined') {
+    exports._ = _;
   } else {
     // Exported as a string, for Closure Compiler "advanced" mode.
     root['_'] = _;

From 1054e24c4fe417f98adc3caeb8ec9cce7b39cdd1 Mon Sep 17 00:00:00 2001
From: Tony Lukasavage 
Date: Tue, 18 Oct 2011 13:27:18 -0300
Subject: [PATCH 08/29] made the exports check safe

---
 underscore.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/underscore.js b/underscore.js
index f09221580..47a330b06 100644
--- a/underscore.js
+++ b/underscore.js
@@ -54,7 +54,7 @@
   if (typeof module !== 'undefined' && module.exports) {
     module.exports = _;
     _._ = _;
-  } else if (exports !== 'undefined') {
+  } else if (typeof exports !== 'undefined' && exports) {
     exports._ = _;
   } else {
     // Exported as a string, for Closure Compiler "advanced" mode.

From 6123870dabb2b1ff8dc52be66c76de0248d78ddc Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Tue, 18 Oct 2011 15:02:06 -0400
Subject: [PATCH 09/29] Fixes #336 ... adds find alias for detect, and reorders
 to make the ES5 versions canonical.

---
 index.html | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/index.html b/index.html
index 5faace35f..3353f7d0f 100644
--- a/index.html
+++ b/index.html
@@ -144,7 +144,7 @@
       

       each, map,
       reduce, reduceRight,
-      detect, select,
+      find, filter,
       reject, all,
       any, include,
       invoke, pluck,
@@ -312,8 +312,9 @@ var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
 => [4, 5, 2, 3, 0, 1]
-

- detect_.detect(list, iterator, [context]) +

+ find_.find(list, iterator, [context]) + Alias: detect
Looks through each value in the list, returning the first one that passes a truth test (iterator). The function returns as @@ -321,20 +322,20 @@ var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []); entire list. 

-var even = _.detect([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
+var even = _.find([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
 => 2
-

- select_.select(list, iterator, [context]) - Alias: filter +

+ filter_.filter(list, iterator, [context]) + Alias: select
Looks through each value in the list, returning an array of all the values that pass a truth test (iterator). Delegates to the native filter method, if it exists. 

-var evens = _.select([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
+var evens = _.filter([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
 => [2, 4, 6]
@@ -342,7 +343,7 @@ var evens = _.select([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; }); reject_.reject(list, iterator, [context])
Returns the values in list without the elements that the truth - test (iterator) passes. The opposite of select. + test (iterator) passes. The opposite of filter. 

 var odds = _.reject([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
@@ -951,7 +952,7 @@ _.clone({name : 'moe'});
       

       
 _([1,2,3,200]).chain().
-  select(function(num) { return num % 2 == 0; }).
+  filter(function(num) { return num % 2 == 0; }).
   tap(console.log).
   map(function(num) { return num * num }).
   value();

From e79586515c5f635650afc32976826e01463dcd1d Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Tue, 18 Oct 2011 16:07:23 -0400
Subject: [PATCH 10/29] Issue #329 -- significant change to _.isEqual
 semantics.

---
 test/objects.js | 12 ++++++------
 underscore.js   | 41 +++++++++++++++--------------------------
 2 files changed, 21 insertions(+), 32 deletions(-)

diff --git a/test/objects.js b/test/objects.js
index c131d920b..5fc4b6a0a 100644
--- a/test/objects.js
+++ b/test/objects.js
@@ -154,8 +154,8 @@ $(document).ready(function() {
     ok(_.isEqual({}, {}), "Empty object literals are equal");
     ok(_.isEqual([], []), "Empty array literals are equal");
     ok(_.isEqual([{}], [{}]), "Empty nested arrays and objects are equal");
-    ok(_.isEqual({length: 0}, []), "Array-like objects and arrays are equal");
-    ok(_.isEqual([], {length: 0}), "Commutative equality is implemented for array-like objects");
+    ok(!_.isEqual({length: 0}, []), "Array-like objects and arrays are not equal.");
+    ok(!_.isEqual([], {length: 0}), "Commutative equality is implemented for array-like objects");
 
     ok(!_.isEqual({}, []), "Object literals and array literals are not equal");
     ok(!_.isEqual([], {}), "Commutative equality is implemented for objects and arrays");
@@ -174,7 +174,7 @@ $(document).ready(function() {
     b.join = b.pop = b.reverse = b.shift = b.slice = b.splice = b.concat = b.sort = b.unshift = null;
 
     // Array elements and properties.
-    ok(_.isEqual(a, b), "Arrays containing equivalent elements and different non-numeric properties are equal");
+    ok(!_.isEqual(a, b), "Arrays containing equivalent elements and different non-numeric properties are not equal");
     a.push("White Rocks");
     ok(!_.isEqual(a, b), "Arrays of different lengths are not equal");
     a.push("East Boulder");
@@ -183,7 +183,7 @@ $(document).ready(function() {
 
     // Sparse arrays.
     ok(_.isEqual(Array(3), Array(3)), "Sparse arrays of identical lengths are equal");
-    ok(!_.isEqual(Array(3), Array(6)), "Sparse arrays of different lengths are not equal");
+    ok(_.isEqual(Array(3), Array(6)), "Sparse arrays of different lengths are equal when both are empty");
 
     // According to the Microsoft deviations spec, section 2.1.26, JScript 5.x treats `undefined`
     // elements in arrays as elisions. Thus, sparse arrays and dense arrays containing `undefined`
@@ -235,8 +235,8 @@ $(document).ready(function() {
 
     // Instances.
     ok(_.isEqual(new First, new First), "Object instances are equal");
-    ok(_.isEqual(new First, new Second), "Objects with different constructors and identical own properties are equal");
-    ok(_.isEqual({value: 1}, new First), "Object instances and objects sharing equivalent properties are identical");
+    ok(!_.isEqual(new First, new Second), "Objects with different constructors and identical own properties are not equal");
+    ok(!_.isEqual({value: 1}, new First), "Object instances and objects sharing equivalent properties are not identical");
     ok(!_.isEqual({value: 2}, new Second), "The prototype chain of objects should not be examined");
 
     // Circular Arrays.
diff --git a/underscore.js b/underscore.js
index d19e26960..5e9d4f3e2 100644
--- a/underscore.js
+++ b/underscore.js
@@ -673,6 +673,8 @@
     }
     // Ensure that both values are objects.
     if (typeA != 'object') return false;
+    // Objects with different constructors are not equal.
+    if (a.constructor !== b.constructor) return false;
     // Assume equality for cyclic structures. The algorithm for detecting cyclic structures is
     // adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
     var length = stack.length;
@@ -684,34 +686,21 @@
     // Add the first object to the stack of traversed objects.
     stack.push(a);
     var size = 0, result = true;
-    if (a.length === +a.length || b.length === +b.length) {
-      // Compare object lengths to determine if a deep comparison is necessary.
-      size = a.length;
-      result = size == b.length;
-      if (result) {
-        // Deep compare array-like object contents, ignoring non-numeric properties.
-        while (size--) {
-          // Ensure commutative equality for sparse arrays.
-          if (!(result = size in a == size in b && eq(a[size], b[size], stack))) break;
-        }
+    // Deep compare objects.
+    for (var key in a) {
+      if (hasOwnProperty.call(a, key)) {
+        // Count the expected number of properties.
+        size++;
+        // Deep compare each member.
+        if (!(result = hasOwnProperty.call(b, key) && eq(a[key], b[key], stack))) break;
       }
-    } else {
-      // Deep compare objects.
-      for (var key in a) {
-        if (hasOwnProperty.call(a, key)) {
-          // Count the expected number of properties.
-          size++;
-          // Deep compare each member.
-          if (!(result = hasOwnProperty.call(b, key) && eq(a[key], b[key], stack))) break;
-        }
-      }
-      // Ensure that both objects contain the same number of properties.
-      if (result) {
-        for (key in b) {
-          if (hasOwnProperty.call(b, key) && !size--) break;
-        }
-        result = !size;
+    }
+    // Ensure that both objects contain the same number of properties.
+    if (result) {
+      for (key in b) {
+        if (hasOwnProperty.call(b, key) && !size--) break;
       }
+      result = !size;
     }
     // Remove the first object from the stack of traversed objects.
     stack.pop();

From 86eedd2a7b2d02c282ce130c508b0c4f4e494789 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Tue, 18 Oct 2011 16:51:45 -0400
Subject: [PATCH 11/29] Fixes #335, exporting for Titanium.

---
 underscore.js | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/underscore.js b/underscore.js
index 84c966ce3..1cb07d815 100644
--- a/underscore.js
+++ b/underscore.js
@@ -48,13 +48,13 @@
   // Create a safe reference to the Underscore object for use below.
   var _ = function(obj) { return new wrapper(obj); };
 
-  // Export the Underscore object for **CommonJS**, with backwards-compatibility
-  // for the old `require()` API. If we're not in CommonJS, add `_` to the
-  // global object.
-  if (typeof module !== 'undefined' && module.exports) {
-    module.exports = _;
-    _._ = _;
-  } else if (typeof exports !== 'undefined' && exports) {
+  // Export the Underscore object for **Node.js** and **"CommonJS"**, with
+  // backwards-compatibility for the old `require()` API. If we're not in
+  // CommonJS, add `_` to the global object.
+  if (typeof exports !== 'undefined') {
+    if (typeof module !== 'undefined' && module.exports) {
+      exports = module.exports = _;
+    }
     exports._ = _;
   } else {
     // Exported as a string, for Closure Compiler "advanced" mode.

From 7fc616943e6ecc43662cb5595f2e839a2ed0172e Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Tue, 18 Oct 2011 23:26:59 -0400
Subject: [PATCH 12/29] Issue #329, special check for the common and magical
 'length' property.

---
 test/objects.js | 2 +-
 underscore.js   | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/test/objects.js b/test/objects.js
index 5fc4b6a0a..e02a76ae4 100644
--- a/test/objects.js
+++ b/test/objects.js
@@ -183,7 +183,7 @@ $(document).ready(function() {
 
     // Sparse arrays.
     ok(_.isEqual(Array(3), Array(3)), "Sparse arrays of identical lengths are equal");
-    ok(_.isEqual(Array(3), Array(6)), "Sparse arrays of different lengths are equal when both are empty");
+    ok(!_.isEqual(Array(3), Array(6)), "Sparse arrays of different lengths are not equal when both are empty");
 
     // According to the Microsoft deviations spec, section 2.1.26, JScript 5.x treats `undefined`
     // elements in arrays as elisions. Thus, sparse arrays and dense arrays containing `undefined`
diff --git a/underscore.js b/underscore.js
index 1cb07d815..d219bc206 100644
--- a/underscore.js
+++ b/underscore.js
@@ -675,6 +675,8 @@
     }
     // Ensure that both values are objects.
     if (typeA != 'object') return false;
+    // Arrays or Arraylikes with different lengths are not equal.
+    if (a.length !== b.length) return false;
     // Objects with different constructors are not equal.
     if (a.constructor !== b.constructor) return false;
     // Assume equality for cyclic structures. The algorithm for detecting cyclic structures is

From 6241343b33959ced28eb7744f85168ef9106c544 Mon Sep 17 00:00:00 2001
From: jrburke 
Date: Wed, 19 Oct 2011 10:07:39 -0700
Subject: [PATCH 13/29] If register as an AMD module, do not create a global,
 since the goal is to not leak out globals in that case.

---
 underscore.js | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/underscore.js b/underscore.js
index c3fe0a53a..2e27c26ac 100644
--- a/underscore.js
+++ b/underscore.js
@@ -56,22 +56,17 @@
       exports = module.exports = _;
     }
     exports._ = _;
-  } else {
-    // Exported as a string, for Closure Compiler "advanced" mode.
-    root['_'] = _;
-
+  } else if (typeof define === 'function' && define.amd) {
     // Register as a module with AMD. Use a named module since underscore
     // can be used in optimization schemes that do not understand anonymous
     // modules, and the if it is used on a page with an AMD loader, a load
-    // error could occur. This work is done in addition to exporting a global
-    // on root since the web page could use an AMD loader to load the module
-    // but still want to use the global reference. Test pages are a good
-    // example.
-    if (typeof define === 'function' && define.amd) {
-      define('underscore', function() {
-        return _;
-      });
-    }
+    // error could occur.
+    define('underscore', function() {
+      return _;
+    });
+  } else {
+    // Exported as a string, for Closure Compiler "advanced" mode.
+    root['_'] = _;
   }
 
   // Current version.

From 3587febd8e45aa53a8eeeae61f5e04899031dfb3 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Wed, 19 Oct 2011 14:47:20 -0400
Subject: [PATCH 14/29] Comment formatting.

---
 underscore.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/underscore.js b/underscore.js
index d219bc206..f2c8c94b7 100644
--- a/underscore.js
+++ b/underscore.js
@@ -679,12 +679,12 @@
     if (a.length !== b.length) return false;
     // Objects with different constructors are not equal.
     if (a.constructor !== b.constructor) return false;
-    // Assume equality for cyclic structures. The algorithm for detecting cyclic structures is
-    // adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
+    // Assume equality for cyclic structures. The algorithm for detecting cyclic
+    // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
     var length = stack.length;
     while (length--) {
-      // Linear search. Performance is inversely proportional to the number of unique nested
-      // structures.
+      // Linear search. Performance is inversely proportional to the number of
+      // unique nested structures.
       if (stack[length] == a) return true;
     }
     // Add the first object to the stack of traversed objects.

From 4b2de2e107465a1916d762fbfebede68a9c55fc9 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Wed, 19 Oct 2011 15:59:53 -0400
Subject: [PATCH 15/29] Fixes #341, flattening arrays in the context of taking
 a union shouldn't be deep. Adding a shallow parameter to _.flatten()

---
 test/arrays.js | 14 ++++++++++----
 underscore.js  |  6 +++---
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/test/arrays.js b/test/arrays.js
index 80da71f6f..c648f081b 100644
--- a/test/arrays.js
+++ b/test/arrays.js
@@ -50,10 +50,13 @@ $(document).ready(function() {
   });
 
   test("arrays: flatten", function() {
-    var list = [1, [2], [3, [[[4]]]]];
-    equals(_.flatten(list).join(', '), '1, 2, 3, 4', 'can flatten nested arrays');
-    var result = (function(){ return _.flatten(arguments); })(1, [2], [3, [[[4]]]]);
-    equals(result.join(', '), '1, 2, 3, 4', 'works on an arguments object');
+    if (window.JSON) {
+      var list = [1, [2], [3, [[[4]]]]];
+      equals(JSON.stringify(_.flatten(list)), '[1,2,3,4]', 'can flatten nested arrays');
+      equals(JSON.stringify(_.flatten(list, true)), '[1,2,3,[[[4]]]]', 'can shallowly flatten nested arrays');
+      var result = (function(){ return _.flatten(arguments); })(1, [2], [3, [[[4]]]]);
+      equals(JSON.stringify(result), '[1,2,3,4]', 'works on an arguments object');
+    }
   });
 
   test("arrays: without", function() {
@@ -97,6 +100,9 @@ $(document).ready(function() {
   test("arrays: union", function() {
     var result = _.union([1, 2, 3], [2, 30, 1], [1, 40]);
     equals(result.join(' '), '1 2 3 30 40', 'takes the union of a list of arrays');
+
+    var result = _.union([1, 2, 3], [2, 30, 1], [1, 40, [1]]);
+    equals(result.join(' '), '1 2 3 30 40 1', 'takes the union of a list of nested arrays');
   });
 
   test("arrays: difference", function() {
diff --git a/underscore.js b/underscore.js
index f2c8c94b7..f2f42898f 100644
--- a/underscore.js
+++ b/underscore.js
@@ -345,9 +345,9 @@
   };
 
   // Return a completely flattened version of an array.
-  _.flatten = function(array) {
+  _.flatten = function(array, shallow) {
     return _.reduce(array, function(memo, value) {
-      if (_.isArray(value)) return memo.concat(_.flatten(value));
+      if (_.isArray(value)) return memo.concat(shallow ? value : _.flatten(value));
       memo[memo.length] = value;
       return memo;
     }, []);
@@ -377,7 +377,7 @@
   // Produce an array that contains the union: each distinct element from all of
   // the passed-in arrays.
   _.union = function() {
-    return _.uniq(_.flatten(arguments));
+    return _.uniq(_.flatten(arguments, true));
   };
 
   // Produce an array that contains every item shared between all the

From f1ba2057317cac2a7d396ac2ac330d40f8481175 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Wed, 19 Oct 2011 16:01:13 -0400
Subject: [PATCH 16/29] cleaning up AMD comment.

---
 underscore.js | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/underscore.js b/underscore.js
index 04f48d0c1..55b72818d 100644
--- a/underscore.js
+++ b/underscore.js
@@ -57,10 +57,7 @@
     }
     exports._ = _;
   } else if (typeof define === 'function' && define.amd) {
-    // Register as a module with AMD. Use a named module since underscore
-    // can be used in optimization schemes that do not understand anonymous
-    // modules, and the if it is used on a page with an AMD loader, a load
-    // error could occur.
+    // Register as a named module with AMD.
     define('underscore', function() {
       return _;
     });

From 3fbb9bb0dd0ae5340642ed5ba4ab46465a63e1c6 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Wed, 19 Oct 2011 16:15:40 -0400
Subject: [PATCH 17/29] Fixes #339 -- incorrect memoization example in docs.

---
 index.html | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/index.html b/index.html
index 3353f7d0f..eae7510e1 100644
--- a/index.html
+++ b/index.html
@@ -751,10 +751,9 @@ jQuery('#underscore_button').bind('click', buttonView.onClick);
         as the key.
       

       
-var fibonacci = function(n) {
+var fibonacci = _.memoize(function(n) {
   return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
-};
-var fastFibonacci = _.memoize(fibonacci);
+});
 

 
       


From 00cd88cfa64cb81fac1a383842c172b7c180d783 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Wed, 19 Oct 2011 16:51:53 -0400
Subject: [PATCH 18/29] Enhancing _.bind() to support binding constructors ...
 which you would never, ever want to do.

---
 test/functions.js |  7 +++++++
 underscore.js     | 18 ++++++++++++++----
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/test/functions.js b/test/functions.js
index af35e5eff..05155eca9 100644
--- a/test/functions.js
+++ b/test/functions.js
@@ -29,6 +29,13 @@ $(document).ready(function() {
     _.bind(func, 0, 0, 'can bind a function to `0`')();
     _.bind(func, '', '', 'can bind a function to an empty string')();
     _.bind(func, false, false, 'can bind a function to `false`')();
+
+    // These tests are only meaningful when using a browser without a native bind function
+    // To test this with a modern browser, set underscore's nativeBind to undefined
+    var F = function () { return this; };
+    var Boundf = _.bind(F, {hello: "moe curly"});
+    equal(new Boundf().hello, undefined, "function should not be bound to the context, to comply with ECMAScript 5");
+    equal(Boundf().hello, "moe curly", "When called without the new operator, it's OK to be bound to the context");
   });
 
   test("functions: bindAll", function() {
diff --git a/underscore.js b/underscore.js
index 55b72818d..a50ac4b81 100644
--- a/underscore.js
+++ b/underscore.js
@@ -464,15 +464,25 @@
   // Function (ahem) Functions
   // ------------------
 
+  // Reusable constructor function for prototype setting.
+  var ctor = function(){};
+
   // Create a function bound to a given object (assigning `this`, and arguments,
   // optionally). Binding with arguments is also known as `curry`.
   // Delegates to **ECMAScript 5**'s native `Function.bind` if available.
   // We check for `func.bind` first, to fail fast when `func` is undefined.
-  _.bind = function(func, obj) {
+  _.bind = function bind(func, context) {
+    var bound, args;
     if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
-    var args = slice.call(arguments, 2);
-    return function() {
-      return func.apply(obj, args.concat(slice.call(arguments)));
+    if (!_.isFunction(func)) throw new TypeError;
+    args = slice.call(arguments, 2);
+    return bound = function() {
+      if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
+      ctor.prototype = func.prototype;
+      var self = new ctor;
+      var result = func.apply(self, args.concat(slice.call(arguments)));
+      if (Object(result) === result) return result;
+      return self;
     };
   };
 

From 42e04ecc7a4c7cef44ce42076141c38dacdce6ab Mon Sep 17 00:00:00 2001
From: Michael Ficarra 
Date: Wed, 19 Oct 2011 23:53:00 -0400
Subject: [PATCH 19/29] execution time optimisations for `_.isArguments`,
 stricter es3 fallback

---
 underscore.js | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/underscore.js b/underscore.js
index 182070eb3..27b458428 100644
--- a/underscore.js
+++ b/underscore.js
@@ -739,9 +739,16 @@
   };
 
   // Is a given variable an arguments object?
-  _.isArguments = function(obj) {
-    return toString.call(obj) == '[object Arguments]' || !!(obj && hasOwnProperty.call(obj, 'callee'));
-  };
+  _.isArguments = toString.call(arguments) == '[object Arguments]'
+    ? function(obj) {
+      return toString.call(obj) == '[object Arguments]';
+    }
+    : function(obj) {
+      return obj
+        ? hasOwnProperty.call(obj, 'callee')
+          && hasOwnProperty.call(obj, 'length')
+        : false;
+    };
 
   // Is a given value a function?
   _.isFunction = function(obj) {

From 4d6e2c6ed4b3b5c91d4cc4170f67e71dc948ae13 Mon Sep 17 00:00:00 2001
From: Michael Ficarra 
Date: Thu, 20 Oct 2011 18:08:08 -0300
Subject: [PATCH 20/29] isNaN comment

---
 underscore.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/underscore.js b/underscore.js
index a50ac4b81..381583ab4 100644
--- a/underscore.js
+++ b/underscore.js
@@ -774,9 +774,9 @@
     return !!(obj === 0 || (obj && obj.toExponential && obj.toFixed));
   };
 
-  // Is the given value `NaN`? `NaN` happens to be the only value in JavaScript
-  // that does not equal itself.
+  // Is the given value `NaN`?
   _.isNaN = function(obj) {
+    // `NaN` is the only value for which `===` is not reflexive.
     return obj !== obj;
   };
 

From 96fdf6fbac96b47c127c5908c96d3c1e640a31ad Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Fri, 21 Oct 2011 14:44:38 -0400
Subject: [PATCH 21/29] Adding the ability to _.groupBy(list, 'account_id')

---
 test/collections.js | 6 ++++++
 underscore.js       | 6 ++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/test/collections.js b/test/collections.js
index cf1c815d6..009d2f327 100644
--- a/test/collections.js
+++ b/test/collections.js
@@ -202,6 +202,12 @@ $(document).ready(function() {
     var parity = _.groupBy([1, 2, 3, 4, 5, 6], function(num){ return num % 2; });
     ok('0' in parity && '1' in parity, 'created a group for each value');
     equals(parity[0].join(', '), '2, 4, 6', 'put each even number in the right group');
+
+    var list = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten"];
+    var grouped = _.groupBy(list, 'length');
+    equals(grouped['3'].join(' '), 'one two six ten');
+    equals(grouped['4'].join(' '), 'four five nine');
+    equals(grouped['5'].join(' '), 'three seven eight');
   });
 
   test('collections: sortedIndex', function() {
diff --git a/underscore.js b/underscore.js
index a50ac4b81..16b076276 100644
--- a/underscore.js
+++ b/underscore.js
@@ -276,9 +276,11 @@
     }), 'value');
   };
 
-  // Groups the object's values by a criterion produced by an iterator
-  _.groupBy = function(obj, iterator) {
+  // Groups the object's values by a criterion. Pass either a string attribute
+  // to group by, or a function that returns the criterion.
+  _.groupBy = function(obj, val) {
     var result = {};
+    var iterator = _.isFunction(val) ? val : function(obj) { return obj[val]; };
     each(obj, function(value, index) {
       var key = iterator(value, index);
       (result[key] || (result[key] = [])).push(value);

From 38b1fe0dd385df94016b4275743d8be7a69891b1 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Mon, 24 Oct 2011 10:12:43 -0400
Subject: [PATCH 22/29] Fixes #345.

---
 underscore.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/underscore.js b/underscore.js
index 86493a085..82dab85e2 100644
--- a/underscore.js
+++ b/underscore.js
@@ -205,8 +205,8 @@
     var found = false;
     if (obj == null) return found;
     if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
-    any(obj, function(value) {
-      if (found = value === target) return true;
+    found = any(obj, function(value) {
+      if (value === target) return true;
     });
     return found;
   };

From 43878e8ef0d4370054cd9aab297b3f0a55ac0722 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Mon, 24 Oct 2011 11:28:26 -0400
Subject: [PATCH 23/29] Merging in #321

---
 underscore.js | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/underscore.js b/underscore.js
index 5d2aece34..72237d180 100644
--- a/underscore.js
+++ b/underscore.js
@@ -758,16 +758,15 @@
   };
 
   // Is a given variable an arguments object?
-  _.isArguments = toString.call(arguments) == '[object Arguments]'
-    ? function(obj) {
+  if (toString.call(arguments) == '[object Arguments]') {
+    _.isArguments = function(obj) {
       return toString.call(obj) == '[object Arguments]';
-    }
-    : function(obj) {
-      return obj
-        ? hasOwnProperty.call(obj, 'callee')
-          && hasOwnProperty.call(obj, 'length')
-        : false;
     };
+  } else {
+    _.isArguments = function(obj) {
+      return !!(obj && hasOwnProperty.call(obj, 'callee'));
+    };
+  }
 
   // Is a given value a function?
   _.isFunction = function(obj) {

From 456a69c559f65330d6a3c981b5b99c8a1ca538f2 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Mon, 24 Oct 2011 11:51:47 -0400
Subject: [PATCH 24/29] fixing documentation for throttle.

---
 index.html | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/index.html b/index.html
index eae7510e1..1b4f4313f 100644
--- a/index.html
+++ b/index.html
@@ -798,11 +798,12 @@ $(window).scroll(throttled);
       

         debounce_.debounce(function, wait)
         

-        Repeated calls to a debounced function will postpone it's execution
-        until after wait milliseconds have elapsed. Useful for implementing
-        behavior that should only happen after the input has stopped arriving.
-        For example: rendering a preview of a Markdown comment, recalculating a
-        layout after the window has stopped being resized...
+        Calling a debounced function will postpone its execution until after 
+        wait milliseconds have elapsed since the last time the function 
+        was invoked. Useful for implementing behavior that should only happen 
+        after the input has stopped arriving. For example: rendering a 
+        preview of a Markdown comment, recalculating a layout after the window 
+        has stopped being resized...
       

       
 var lazyLayout = _.debounce(calculateLayout, 300);

From bceb77e325839277b2a03b34d1247e7d555cd0ac Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Mon, 24 Oct 2011 12:05:59 -0400
Subject: [PATCH 25/29] Fixes #170, #266 ... throttle now starts at the
 beginning of the call.

---
 test/functions.js |  3 ++-
 underscore.js     | 36 +++++++++++++++++++-----------------
 2 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/test/functions.js b/test/functions.js
index 05155eca9..fa74f26ea 100644
--- a/test/functions.js
+++ b/test/functions.js
@@ -90,7 +90,7 @@ $(document).ready(function() {
     _.delay(function(){ ok(deferred, "deferred the function"); start(); }, 50);
   });
 
-  asyncTest("functions: throttle", 1, function() {
+  asyncTest("functions: throttle", 2, function() {
     var counter = 0;
     var incr = function(){ counter++; };
     var throttledIncr = _.throttle(incr, 100);
@@ -99,6 +99,7 @@ $(document).ready(function() {
     setTimeout(throttledIncr, 140);
     setTimeout(throttledIncr, 220);
     setTimeout(throttledIncr, 240);
+    _.delay(function(){ ok(counter == 1, "incr throttle was called immediately"); }, 40);
     _.delay(function(){ ok(counter == 3, "incr was throttled"); start(); }, 400);
   });
 
diff --git a/underscore.js b/underscore.js
index 72237d180..d5279f4b6 100644
--- a/underscore.js
+++ b/underscore.js
@@ -520,8 +520,23 @@
     return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
   };
 
-  // Internal function used to implement `_.throttle` and `_.debounce`.
-  var limit = function(func, wait, debounce) {
+  // Returns a function, that, when invoked, will only be triggered at most once
+  // during a given window of time.
+  _.throttle = function(func, wait) {
+    var ran = false;
+    return function() {
+      if (!ran) {
+        ran = true;
+        setTimeout(function(){ ran = false; }, wait);
+        return func.apply(this, arguments);
+      }
+    };
+  };
+
+  // Returns a function, that, as long as it continues to be invoked, will not
+  // be triggered. The function will be called after it stops being called for
+  // N milliseconds.
+  _.debounce = function(func, wait) {
     var timeout;
     return function() {
       var context = this, args = arguments;
@@ -529,24 +544,11 @@
         timeout = null;
         func.apply(context, args);
       };
-      if (debounce) clearTimeout(timeout);
-      if (debounce || !timeout) timeout = setTimeout(throttler, wait);
+      if (timeout) clearTimeout(timeout);
+      timeout = setTimeout(throttler, wait);
     };
   };
 
-  // Returns a function, that, when invoked, will only be triggered at most once
-  // during a given window of time.
-  _.throttle = function(func, wait) {
-    return limit(func, wait, false);
-  };
-
-  // Returns a function, that, as long as it continues to be invoked, will not
-  // be triggered. The function will be called after it stops being called for
-  // N milliseconds.
-  _.debounce = function(func, wait) {
-    return limit(func, wait, true);
-  };
-
   // Returns a function that will be executed at most one time, no matter how
   // often you call it. Useful for lazy initialization.
   _.once = function(func) {

From cfec39fd4e1dd790a92c348ff98dee1252c851b4 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Mon, 24 Oct 2011 12:06:55 -0400
Subject: [PATCH 26/29] Revert "Fixes #170, #266 ... throttle now starts at the
 beginning of the call."

This reverts commit bceb77e325839277b2a03b34d1247e7d555cd0ac.
---
 test/functions.js |  3 +--
 underscore.js     | 36 +++++++++++++++++-------------------
 2 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/test/functions.js b/test/functions.js
index fa74f26ea..05155eca9 100644
--- a/test/functions.js
+++ b/test/functions.js
@@ -90,7 +90,7 @@ $(document).ready(function() {
     _.delay(function(){ ok(deferred, "deferred the function"); start(); }, 50);
   });
 
-  asyncTest("functions: throttle", 2, function() {
+  asyncTest("functions: throttle", 1, function() {
     var counter = 0;
     var incr = function(){ counter++; };
     var throttledIncr = _.throttle(incr, 100);
@@ -99,7 +99,6 @@ $(document).ready(function() {
     setTimeout(throttledIncr, 140);
     setTimeout(throttledIncr, 220);
     setTimeout(throttledIncr, 240);
-    _.delay(function(){ ok(counter == 1, "incr throttle was called immediately"); }, 40);
     _.delay(function(){ ok(counter == 3, "incr was throttled"); start(); }, 400);
   });
 
diff --git a/underscore.js b/underscore.js
index d5279f4b6..72237d180 100644
--- a/underscore.js
+++ b/underscore.js
@@ -520,23 +520,8 @@
     return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
   };
 
-  // Returns a function, that, when invoked, will only be triggered at most once
-  // during a given window of time.
-  _.throttle = function(func, wait) {
-    var ran = false;
-    return function() {
-      if (!ran) {
-        ran = true;
-        setTimeout(function(){ ran = false; }, wait);
-        return func.apply(this, arguments);
-      }
-    };
-  };
-
-  // Returns a function, that, as long as it continues to be invoked, will not
-  // be triggered. The function will be called after it stops being called for
-  // N milliseconds.
-  _.debounce = function(func, wait) {
+  // Internal function used to implement `_.throttle` and `_.debounce`.
+  var limit = function(func, wait, debounce) {
     var timeout;
     return function() {
       var context = this, args = arguments;
@@ -544,11 +529,24 @@
         timeout = null;
         func.apply(context, args);
       };
-      if (timeout) clearTimeout(timeout);
-      timeout = setTimeout(throttler, wait);
+      if (debounce) clearTimeout(timeout);
+      if (debounce || !timeout) timeout = setTimeout(throttler, wait);
     };
   };
 
+  // Returns a function, that, when invoked, will only be triggered at most once
+  // during a given window of time.
+  _.throttle = function(func, wait) {
+    return limit(func, wait, false);
+  };
+
+  // Returns a function, that, as long as it continues to be invoked, will not
+  // be triggered. The function will be called after it stops being called for
+  // N milliseconds.
+  _.debounce = function(func, wait) {
+    return limit(func, wait, true);
+  };
+
   // Returns a function that will be executed at most one time, no matter how
   // often you call it. Useful for lazy initialization.
   _.once = function(func) {

From b4d950334052ee5e03f697122f7554ebfba9aeb3 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Mon, 24 Oct 2011 13:13:24 -0400
Subject: [PATCH 27/29] fixes #170, fixes #266 ... reimplementing throttle in
 terms of debounce.

---
 test/functions.js | 20 ++++++++++++++++++--
 underscore.js     | 42 +++++++++++++++++++++++++-----------------
 2 files changed, 43 insertions(+), 19 deletions(-)

diff --git a/test/functions.js b/test/functions.js
index 05155eca9..5bcf215b7 100644
--- a/test/functions.js
+++ b/test/functions.js
@@ -90,16 +90,32 @@ $(document).ready(function() {
     _.delay(function(){ ok(deferred, "deferred the function"); start(); }, 50);
   });
 
-  asyncTest("functions: throttle", 1, function() {
+  asyncTest("functions: throttle", 2, function() {
     var counter = 0;
     var incr = function(){ counter++; };
     var throttledIncr = _.throttle(incr, 100);
     throttledIncr(); throttledIncr(); throttledIncr();
+    setTimeout(throttledIncr, 70);
     setTimeout(throttledIncr, 120);
     setTimeout(throttledIncr, 140);
+    setTimeout(throttledIncr, 190);
     setTimeout(throttledIncr, 220);
     setTimeout(throttledIncr, 240);
-    _.delay(function(){ ok(counter == 3, "incr was throttled"); start(); }, 400);
+    _.delay(function(){ ok(counter == 1, "incr was called immediately"); }, 30);
+    _.delay(function(){ ok(counter == 4, "incr was throttled"); start(); }, 400);
+  });
+
+  asyncTest("functions: throttle arguments", 2, function() {
+    var value = 0;
+    var update = function(val){ value = val; };
+    var throttledUpdate = _.throttle(update, 100);
+    throttledUpdate(1); throttledUpdate(2); throttledUpdate(3);
+    setTimeout(function(){ throttledUpdate(4); }, 120);
+    setTimeout(function(){ throttledUpdate(5); }, 140);
+    setTimeout(function(){ throttledUpdate(6); }, 260);
+    setTimeout(function(){ throttledUpdate(7); }, 270);
+    _.delay(function(){ ok(value == 1, "updated to latest value"); }, 40);
+    _.delay(function(){ ok(value == 7, "updated to latest value"); start(); }, 400);
   });
 
   asyncTest("functions: debounce", 1, function() {
diff --git a/underscore.js b/underscore.js
index 72237d180..04f3311cd 100644
--- a/underscore.js
+++ b/underscore.js
@@ -520,8 +520,29 @@
     return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
   };
 
-  // Internal function used to implement `_.throttle` and `_.debounce`.
-  var limit = function(func, wait, debounce) {
+  // Returns a function, that, when invoked, will only be triggered at most once
+  // during a given window of time.
+  _.throttle = function(func, wait) {
+    var timeout, context, args, throttling, finishThrottle;
+    finishThrottle = _.debounce(function(){ throttling = false; }, wait);
+    return function() {
+      context = this; args = arguments;
+      var throttler = function() {
+        timeout = null;
+        func.apply(context, args);
+        finishThrottle();
+      };
+      if (!timeout) timeout = setTimeout(throttler, wait);
+      if (!throttling) func.apply(context, args);
+      if (finishThrottle) finishThrottle();
+      throttling = true;
+    };
+  };
+
+  // Returns a function, that, as long as it continues to be invoked, will not
+  // be triggered. The function will be called after it stops being called for
+  // N milliseconds.
+  _.debounce = function(func, wait) {
     var timeout;
     return function() {
       var context = this, args = arguments;
@@ -529,24 +550,11 @@
         timeout = null;
         func.apply(context, args);
       };
-      if (debounce) clearTimeout(timeout);
-      if (debounce || !timeout) timeout = setTimeout(throttler, wait);
+      clearTimeout(timeout);
+      timeout = setTimeout(throttler, wait);
     };
   };
 
-  // Returns a function, that, when invoked, will only be triggered at most once
-  // during a given window of time.
-  _.throttle = function(func, wait) {
-    return limit(func, wait, false);
-  };
-
-  // Returns a function, that, as long as it continues to be invoked, will not
-  // be triggered. The function will be called after it stops being called for
-  // N milliseconds.
-  _.debounce = function(func, wait) {
-    return limit(func, wait, true);
-  };
-
   // Returns a function that will be executed at most one time, no matter how
   // often you call it. Useful for lazy initialization.
   _.once = function(func) {

From 3c54f7911339261f0e54dc3451d8ae981ca42df9 Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Mon, 24 Oct 2011 13:19:15 -0400
Subject: [PATCH 28/29] fixes #347

---
 test/objects.js | 4 ++++
 underscore.js   | 1 +
 2 files changed, 5 insertions(+)

diff --git a/test/objects.js b/test/objects.js
index 967ba6b21..7e6cd7cc1 100644
--- a/test/objects.js
+++ b/test/objects.js
@@ -66,6 +66,10 @@ $(document).ready(function() {
 
     clone.lucky.push(101);
     equals(_.last(moe.lucky), 101, 'changes to deep attributes are shared with the original');
+
+    equals(_.clone(undefined), void 0, 'non objects should not be changed by clone');
+    equals(_.clone(1), 1, 'non objects should not be changed by clone');
+    equals(_.clone(null), null, 'non objects should not be changed by clone');
   });
 
   test("objects: isEqual", function() {
diff --git a/underscore.js b/underscore.js
index 04f3311cd..5470fa6b3 100644
--- a/underscore.js
+++ b/underscore.js
@@ -645,6 +645,7 @@
 
   // Create a (shallow-cloned) duplicate of an object.
   _.clone = function(obj) {
+    if (!_.isObject(obj)) return obj;
     return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
   };
 

From bffdb50f9bb1f44252c5d5e53c48afef5065ad4a Mon Sep 17 00:00:00 2001
From: Jeremy Ashkenas 
Date: Mon, 24 Oct 2011 14:23:36 -0400
Subject: [PATCH 29/29] Underscore.js 1.2.1

---
 docs/underscore.html | 297 +++++++++++++++++++++++--------------------
 index.html           |  72 +++++++----
 package.json         |   2 +-
 underscore-min.js    |  47 +++----
 underscore.js        |   4 +-
 5 files changed, 236 insertions(+), 186 deletions(-)

diff --git a/docs/underscore.html b/docs/underscore.html
index 726b8976a..6e44f0cf8 100644
--- a/docs/underscore.html
+++ b/docs/underscore.html
@@ -1,4 +1,4 @@
-      underscore.js           
     
          
                
                        
               underscore.js             
           		                               
                                             
                            
                                
               
Underscore.js 1.2.0
+      underscore.js           
     
          iterator(array[mid])<iterator(obj)?low=mid+1:high=mid;}returnlow;
-  };return_.indexOf(other,item)>=0;});});
-  };if(nativeIndexOf&&array.indexOf===nativeIndexOf)returnarray.indexOf(item);for(i=0,l=array.length;i<l;i++)if(array[i]===item)returni;return-1;
-  };ran=true;returnmemo=func.apply(this,arguments);};
-  };}returnargs[0];};
-  };+"');}return __p.join('');";varfunc=newFunction('obj',tmpl);returndata?func(data):func;
-  };
                
                        
               underscore.js             
           		                               
                                             
                            
                                
               
Underscore.js 1.2.1
 (c) 2011 Jeremy Ashkenas, DocumentCloud Inc.
 Underscore is freely distributable under the MIT license.
 Portions of Underscore are inspired or borrowed from Prototype,
@@ -21,13 +21,18 @@ are declared here.
             
             
     nativeLastIndexOf  = ArrayProto.lastIndexOf,
     nativeIsArray      = Array.isArray,
     nativeKeys         = Object.keys,
-    nativeBind         = FuncProto.bind;                        
                               
                            
                                
               
Create a safe reference to the Underscore object for use below.
             		                            
  var _ = function(obj) { return new wrapper(obj); };
             		           
                               
                            
                                
               
Export the Underscore object for CommonJS, with backwards-compatibility
-for the old require() API. If we're not in CommonJS, add _ to the
-global object.
             		                            
  if (typeof module !== 'undefined' && module.exports) {
-    module.exports = _;
-    _._ = _;
-  } else {
             		           
                               
                            
                                
               
Exported as a string, for Closure Compiler "advanced" mode.
             		                            
    root['_'] = _;
-  }
             		           
                               
                            
                                
               
Current version.
             		                            
  _.VERSION = '1.2.0';
             		           
                               
                            
                                
               
Collection Functions
             		                            
             		           
                               
                            
                                
               
The cornerstone, an each implementation, aka forEach.
+    nativeBind         = FuncProto.bind;             
           
                               
                            
                                
               
Create a safe reference to the Underscore object for use below.
             		                            
  var _ = function(obj) { return new wrapper(obj); };
             		           
                               
                            
                                
               
Export the Underscore object for Node.js and "CommonJS", with
+backwards-compatibility for the old require() API. If we're not in
+CommonJS, add _ to the global object.
             		                            
  if (typeof exports !== 'undefined') {
+    if (typeof module !== 'undefined' && module.exports) {
+      exports = module.exports = _;
+    }
+    exports._ = _;
+  } else if (typeof define === 'function' && define.amd) {
             		           
                               
                            
                                
               
Register as a named module with AMD.
             		                            
    define('underscore', function() {
+      return _;
+    });
+  } else {
             		           
                               
                            
                                
               
Exported as a string, for Closure Compiler "advanced" mode.
             		                            
    root['_'] = _;
+  }
             		           
                               
                            
                                
               
Current version.
             		                            
  _.VERSION = '1.2.1';
             		           
                               
                            
                                
               
Collection Functions
             		                            
             		           
                               
                            
                                
               
The cornerstone, an each implementation, aka forEach.
 Handles objects with the built-in forEach, arrays, and raw objects.
 Delegates to ECMAScript 5's native forEach if available.
             		                            
  var each = _.each = _.forEach = function(obj, iterator, context) {
     if (obj == null) return;
@@ -44,7 +49,7 @@ Delegates to ECMAScript 5's native forEach if avai
         }
       }
     }
-  };
             		           
                               
                            
                                
               
Return the results of applying the iterator to each element.
+  };             
           
                               
                            
                                
               
Return the results of applying the iterator to each element.
 Delegates to ECMAScript 5's native map if available.
             		                            
  _.map = function(obj, iterator, context) {
     var results = [];
     if (obj == null) return results;
@@ -53,7 +58,7 @@ Delegates to ECMAScript 5's native map if availabl
       results[results.length] = iterator.call(context, value, index, list);
     });
     return results;
-  };
             		           
                               
                            
                                
               
Reduce builds up a single result from a list of values, aka inject,
+  };             
           
                               
                            
                                
               
Reduce builds up a single result from a list of values, aka inject,
 or foldl. Delegates to ECMAScript 5's native reduce if available.
             		                            
  _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
     var initial = memo !== void 0;
     if (obj == null) obj = [];
@@ -71,7 +76,7 @@ or foldl. Delegates to ECMAScript 5's native });
     if (!initial) throw new TypeError("Reduce of empty array with no initial value");
     return memo;
-  };
             		           
                               
                            
                                
               
The right-associative version of reduce, also known as foldr.
+  };             
           
                               
                            
                                
               
The right-associative version of reduce, also known as foldr.
 Delegates to ECMAScript 5's native reduceRight if available.
             		                            
  _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
     if (obj == null) obj = [];
     if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
@@ -80,7 +85,7 @@ Delegates to ECMAScript 5's native reduceRight if
     }
     var reversed = (_.isArray(obj) ? obj.slice() : _.toArray(obj)).reverse();
     return _.reduce(reversed, iterator, memo, context);
-  };
             		           
                               
                            
                                
               
Return the first value which passes a truth test. Aliased as detect.
             		                            
  _.find = _.detect = function(obj, iterator, context) {
+  };
             		           
                               
                            
                                
               
Return the first value which passes a truth test. Aliased as detect.
             		                            
  _.find = _.detect = function(obj, iterator, context) {
     var result;
     any(obj, function(value, index, list) {
       if (iterator.call(context, value, index, list)) {
@@ -89,7 +94,7 @@ Delegates to ECMAScript 5's native reduceRight if
       }
     });
     return result;
-  };
             		           
                               
                            
                                
               
Return all the elements that pass a truth test.
+  };             
           
                               
                            
                                
               
Return all the elements that pass a truth test.
 Delegates to ECMAScript 5's native filter if available.
 Aliased as select.
             		                            
  _.filter = _.select = function(obj, iterator, context) {
     var results = [];
@@ -99,14 +104,14 @@ Aliased as select.
             
             if (iterator.call(context, value, index, list)) results[results.length] = value;
     });
     return results;
-  };                        
                               
                            
                                
               
Return all the elements for which a truth test fails.
             		                            
  _.reject = function(obj, iterator, context) {
+  };
             		           
                               
                            
                                
               
Return all the elements for which a truth test fails.
             		                            
  _.reject = function(obj, iterator, context) {
     var results = [];
     if (obj == null) return results;
     each(obj, function(value, index, list) {
       if (!iterator.call(context, value, index, list)) results[results.length] = value;
     });
     return results;
-  };
             		           
                               
                            
                                
               
Determine whether all of the elements match a truth test.
+  };             
           
                               
                            
                                
               
Determine whether all of the elements match a truth test.
 Delegates to ECMAScript 5's native every if available.
 Aliased as all.
             		                            
  _.every = _.all = function(obj, iterator, context) {
     var result = true;
@@ -116,7 +121,7 @@ Aliased as all.
             
             
       if (!(result = result && iterator.call(context, value, index, list))) return breaker;
     });
     return result;
-  };                        
                               
                            
                                
               
Determine if at least one element in the object matches a truth test.
+  };             
           
                               
                            
                                
               
Determine if at least one element in the object matches a truth test.
 Delegates to ECMAScript 5's native some if available.
 Aliased as any.
             		                            
  var any = _.some = _.any = function(obj, iterator, context) {
     iterator = iterator || _.identity;
@@ -127,23 +132,23 @@ Aliased as any.
             
             
       if (result |= iterator.call(context, value, index, list)) return breaker;
     });
     return !!result;
-  };                        
                               
                            
                                
               
Determine if a given value is included in the array or object using ===.
+  };             
           
                               
                            
                                
               
Determine if a given value is included in the array or object using ===.
 Aliased as contains.
             		                            
  _.include = _.contains = function(obj, target) {
     var found = false;
     if (obj == null) return found;
     if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
-    any(obj, function(value) {
-      if (found = value === target) return true;
+    found = any(obj, function(value) {
+      if (value === target) return true;
     });
     return found;
-  };
             		           
                               
                            
                                
               
Invoke a method (with arguments) on every item in a collection.
             		                            
  _.invoke = function(obj, method) {
+  };
             		           
                               
                            
                                
               
Invoke a method (with arguments) on every item in a collection.
             		                            
  _.invoke = function(obj, method) {
     var args = slice.call(arguments, 2);
     return _.map(obj, function(value) {
       return (method.call ? method || value : value[method]).apply(value, args);
     });
-  };
             		           
                               
                            
                                
               
Convenience version of a common use case of map: fetching a property.
             		                            
  _.pluck = function(obj, key) {
+  };
             		           
                               
                            
                                
               
Convenience version of a common use case of map: fetching a property.
             		                            
  _.pluck = function(obj, key) {
     return _.map(obj, function(value){ return value[key]; });
-  };
             		           
                               
                            
                                
               
Return the maximum element or (element-based computation).
             		                            
  _.max = function(obj, iterator, context) {
+  };
             		           
                               
                            
                                
               
Return the maximum element or (element-based computation).
             		                            
  _.max = function(obj, iterator, context) {
     if (!iterator && _.isArray(obj)) return Math.max.apply(Math, obj);
     if (!iterator && _.isEmpty(obj)) return -Infinity;
     var result = {computed : -Infinity};
@@ -152,7 +157,7 @@ Aliased as contains.
             
             computed >= result.computed && (result = {value : value, computed : computed});
     });
     return result.value;
-  };                        
                               
                            
                                
               
Return the minimum element (or element-based computation).
             		                            
  _.min = function(obj, iterator, context) {
+  };
             		           
                               
                            
                                
               
Return the minimum element (or element-based computation).
             		                            
  _.min = function(obj, iterator, context) {
     if (!iterator && _.isArray(obj)) return Math.min.apply(Math, obj);
     if (!iterator && _.isEmpty(obj)) return Infinity;
     var result = {computed : Infinity};
@@ -161,7 +166,7 @@ Aliased as contains.
             
             computed < result.computed && (result = {value : value, computed : computed});
     });
     return result.value;
-  };                        
                               
                            
                                
               
Shuffle an array.
             		                            
  _.shuffle = function(obj) {
+  };
             		           
                               
                            
                                
               
Shuffle an array.
             		                            
  _.shuffle = function(obj) {
     var shuffled = [], rand;
     each(obj, function(value, index, list) {
       if (index == 0) {
@@ -173,7 +178,7 @@ Aliased as contains.
             
             }
     });
     return shuffled;
-  };                        
                               
                            
                                
               
Sort the object's values by a criterion produced by an iterator.
             		                            
  _.sortBy = function(obj, iterator, context) {
+  };
             		           
                               
                            
                                
               
Sort the object's values by a criterion produced by an iterator.
             		                            
  _.sortBy = function(obj, iterator, context) {
     return _.pluck(_.map(obj, function(value, index, list) {
       return {
         value : value,
@@ -183,14 +188,16 @@ Aliased as contains.
             
             var a = left.criteria, b = right.criteria;
       return a < b ? -1 : a > b ? 1 : 0;
     }), 'value');
-  };                        
                               
                            
                                
               
Groups the object's values by a criterion produced by an iterator
             		                            
  _.groupBy = function(obj, iterator) {
+  };
             		           
                               
                            
                                
               
Groups the object's values by a criterion. Pass either a string attribute
+to group by, or a function that returns the criterion.
             		                            
  _.groupBy = function(obj, val) {
     var result = {};
+    var iterator = _.isFunction(val) ? val : function(obj) { return obj[val]; };
     each(obj, function(value, index) {
       var key = iterator(value, index);
       (result[key] || (result[key] = [])).push(value);
     });
     return result;
-  };
             		           
                               
                            
                                
               
Use a comparator function to figure out at what index an object should
+  };             
           
                               
                            
                                
               
Use a comparator function to figure out at what index an object should
 be inserted so as to maintain order. Uses binary search.
             		                            
  _.sortedIndex = function(array, obj, iterator) {
     iterator || (iterator = _.identity);
     var low = 0, high = array.length;
@@ -199,42 +206,42 @@ be inserted so as to maintain order. Uses binary search.
             

                   
     
                              
                               
                            
                                
               
Safely convert anything iterable into a real, live array.
             		                            
  _.toArray = function(iterable) {
+  };
             		           
                               
                            
                                
               
Safely convert anything iterable into a real, live array.
             		                            
  _.toArray = function(iterable) {
     if (!iterable)                return [];
     if (iterable.toArray)         return iterable.toArray();
     if (_.isArray(iterable))      return slice.call(iterable);
     if (_.isArguments(iterable))  return slice.call(iterable);
     return _.values(iterable);
-  };
             		           
                               
                            
                                
               
Return the number of elements in an object.
             		                            
  _.size = function(obj) {
+  };
             		           
                               
                            
                                
               
Return the number of elements in an object.
             		                            
  _.size = function(obj) {
     return _.toArray(obj).length;
-  };
             		           
                               
                            
                                
               
Array Functions
             		                            
             		           
                               
                            
                                
               
Get the first element of an array. Passing n will return the first N
+  };             
           
                               
                            
                                
               
Array Functions
             		                            
             		           
                               
                            
                                
               
Get the first element of an array. Passing n will return the first N
 values in the array. Aliased as head. The guard check allows it to work
 with _.map.
             		                            
  _.first = _.head = function(array, n, guard) {
     return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
-  };
             		           
                               
                            
                                
               
Returns everything but the last entry of the array. Especcialy useful on
+  };             
           
                               
                            
                                
               
Returns everything but the last entry of the array. Especcialy useful on
 the arguments object. Passing n will return all the values in
 the array, excluding the last N. The guard check allows it to work with
 _.map.
             		                            
  _.initial = function(array, n, guard) {
     return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
-  };
             		           
                               
                            
                                
               
Get the last element of an array. Passing n will return the last N
+  };             
           
                               
                            
                                
               
Get the last element of an array. Passing n will return the last N
 values in the array. The guard check allows it to work with _.map.
             		                            
  _.last = function(array, n, guard) {
     return (n != null) && !guard ? slice.call(array, array.length - n) : array[array.length - 1];
-  };
             		           
                               
                            
                                
               
Returns everything but the first entry of the array. Aliased as tail.
+  };             
           
                               
                            
                                
               
Returns everything but the first entry of the array. Aliased as tail.
 Especially useful on the arguments object. Passing an index will return
 the rest of the values in the array from that index onward. The guard
 check allows it to work with _.map.
             		                            
  _.rest = _.tail = function(array, index, guard) {
     return slice.call(array, (index == null) || guard ? 1 : index);
-  };
             		           
                               
                            
                                
               
Trim out all falsy values from an array.
             		                            
  _.compact = function(array) {
+  };
             		           
                               
                            
                                
               
Trim out all falsy values from an array.
             		                            
  _.compact = function(array) {
     return _.filter(array, function(value){ return !!value; });
-  };
             		           
                               
                            
                                
               
Return a completely flattened version of an array.
             		                            
  _.flatten = function(array) {
+  };
             		           
                               
                            
                                
               
Return a completely flattened version of an array.
             		                            
  _.flatten = function(array, shallow) {
     return _.reduce(array, function(memo, value) {
-      if (_.isArray(value)) return memo.concat(_.flatten(value));
+      if (_.isArray(value)) return memo.concat(shallow ? value : _.flatten(value));
       memo[memo.length] = value;
       return memo;
     }, []);
-  };
             		           
                               
                            
                                
               
Return a version of the array that does not contain the specified value(s).
             		                            
  _.without = function(array) {
+  };
             		           
                               
                            
                                
               
Return a version of the array that does not contain the specified value(s).
             		                            
  _.without = function(array) {
     return _.difference(array, slice.call(arguments, 1));
-  };
             		           
                               
                            
                                
               
Produce a duplicate-free version of the array. If the array has already
+  };             
           
                               
                            
                                
               
Produce a duplicate-free version of the array. If the array has already
 been sorted, you have the option of using a faster algorithm.
 Aliased as unique.
             		                            
  _.uniq = _.unique = function(array, isSorted, iterator) {
     var initial = iterator ? _.map(array, iterator) : array;
@@ -247,10 +254,10 @@ Aliased as unique.
             
             return memo;
     }, []);
     return result;
-  };                        
                               
                            
                                
               
Produce an array that contains the union: each distinct element from all of
+  };             
           
                               
                            
                                
               
Produce an array that contains the union: each distinct element from all of
 the passed-in arrays.
             		                            
  _.union = function() {
-    return _.uniq(_.flatten(arguments));
-  };
             		           
                               
                            
                                
               
Produce an array that contains every item shared between all the
+    return _.uniq(_.flatten(arguments, true));
+  };             
           
                               
                            
                                
               
Produce an array that contains every item shared between all the
 passed-in arrays. (Aliased as "intersect" for back-compat.)
             		                            
  _.intersection = _.intersect = function(array) {
     var rest = slice.call(arguments, 1);
     return _.filter(_.uniq(array), function(item) {
@@ -258,17 +265,17 @@ passed-in arrays. (Aliased as "intersect" for back-compat.)
             
    
       
                             
                               
                            
                                
               
Take the difference between one array and another.
+  };             
           
                               
                            
                                
               
Take the difference between one array and another.
 Only the elements present in just the first array will remain.
             		                            
  _.difference = function(array, other) {
     return _.filter(array, function(value){ return !_.include(other, value); });
-  };
             		           
                               
                            
                                
               
Zip together multiple lists into a single array -- elements that share
+  };             
           
                               
                            
                                
               
Zip together multiple lists into a single array -- elements that share
 an index go together.
             		                            
  _.zip = function() {
     var args = slice.call(arguments);
     var length = _.max(_.pluck(args, 'length'));
     var results = new Array(length);
     for (var i = 0; i < length; i++) results[i] = _.pluck(args, "" + i);
     return results;
-  };
             		           
                               
                            
                                
               
If the browser doesn't supply us with indexOf (I'm looking at you, MSIE),
+  };             
           
                               
                            
                                
               
If the browser doesn't supply us with indexOf (I'm looking at you, MSIE),
 we need this function. Return the position of the first occurrence of an
 item in an array, or -1 if the item is not included in the array.
 Delegates to ECMAScript 5's native indexOf if available.
@@ -283,13 +290,13 @@ for isSorted to use binary search.
             		
            
                     
                              
                               
                            
                                
               
Delegates to ECMAScript 5's native lastIndexOf if available.
             		                            
  _.lastIndexOf = function(array, item) {
+  };
             		           
                               
                            
                                
               
Delegates to ECMAScript 5's native lastIndexOf if available.
             		                            
  _.lastIndexOf = function(array, item) {
     if (array == null) return -1;
     if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) return array.lastIndexOf(item);
     var i = array.length;
     while (i--) if (array[i] === item) return i;
     return -1;
-  };
             		           
                               
                            
                                
               
Generate an integer Array containing an arithmetic progression. A port of
+  };             
           
                               
                            
                                
               
Generate an integer Array containing an arithmetic progression. A port of
 the native Python range() function. See
 the Python documentation.
             		                            
  _.range = function(start, stop, step) {
     if (arguments.length <= 1) {
@@ -308,36 +315,61 @@ the native Python range() function. See
     }
 
     return range;
-  };
             		           
                               
                            
                                
               
Function (ahem) Functions
             		                            
             		           
                               
                            
                                
               
Create a function bound to a given object (assigning this, and arguments,
+  };             
           
                               
                            
                                
               
Function (ahem) Functions
             		                            
             		           
                               
                            
                                
               
Reusable constructor function for prototype setting.
             		                            
  var ctor = function(){};
             		           
                               
                            
                                
               
Create a function bound to a given object (assigning this, and arguments,
 optionally). Binding with arguments is also known as curry.
 Delegates to ECMAScript 5's native Function.bind if available.
-We check for func.bind first, to fail fast when func is undefined.
             		                            
  _.bind = function(func, obj) {
+We check for func.bind first, to fail fast when func is undefined.
             
                            
  _.bind = function bind(func, context) {
+    var bound, args;
     if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
-    var args = slice.call(arguments, 2);
-    return function() {
-      return func.apply(obj, args.concat(slice.call(arguments)));
+    if (!_.isFunction(func)) throw new TypeError;
+    args = slice.call(arguments, 2);
+    return bound = function() {
+      if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
+      ctor.prototype = func.prototype;
+      var self = new ctor;
+      var result = func.apply(self, args.concat(slice.call(arguments)));
+      if (Object(result) === result) return result;
+      return self;
     };
-  };
             		           
                               
                            
                                
               
Bind all of an object's methods to that object. Useful for ensuring that
+  };             
           
                               
                            
                                
               
Bind all of an object's methods to that object. Useful for ensuring that
 all callbacks defined on an object belong to it.
             		                            
  _.bindAll = function(obj) {
     var funcs = slice.call(arguments, 1);
     if (funcs.length == 0) funcs = _.functions(obj);
     each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); });
     return obj;
-  };
             		           
                               
                            
                                
               
Memoize an expensive function by storing its results.
             		                            
  _.memoize = function(func, hasher) {
+  };
             		           
                               
                            
                                
               
Memoize an expensive function by storing its results.
             		                            
  _.memoize = function(func, hasher) {
     var memo = {};
     hasher || (hasher = _.identity);
     return function() {
       var key = hasher.apply(this, arguments);
       return hasOwnProperty.call(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
     };
-  };
             		           
                               
                            
                                
               
Delays a function for the given number of milliseconds, and then calls
+  };             
           
                               
                            
                                
               
Delays a function for the given number of milliseconds, and then calls
 it with the arguments supplied.
             		                            
  _.delay = function(func, wait) {
     var args = slice.call(arguments, 2);
     return setTimeout(function(){ return func.apply(func, args); }, wait);
-  };
             		           
                               
                            
                                
               
Defers a function, scheduling it to run after the current call stack has
+  };             
           
                               
                            
                                
               
Defers a function, scheduling it to run after the current call stack has
 cleared.
             		                            
  _.defer = function(func) {
     return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
-  };
             		           
                               
                            
                                
               
Internal function used to implement _.throttle and _.debounce.
             		                            
  var limit = function(func, wait, debounce) {
+  };
             		           
                               
                            
                                
               
Returns a function, that, when invoked, will only be triggered at most once
+during a given window of time.
             		                            
  _.throttle = function(func, wait) {
+    var timeout, context, args, throttling, finishThrottle;
+    finishThrottle = _.debounce(function(){ throttling = false; }, wait);
+    return function() {
+      context = this; args = arguments;
+      var throttler = function() {
+        timeout = null;
+        func.apply(context, args);
+        finishThrottle();
+      };
+      if (!timeout) timeout = setTimeout(throttler, wait);
+      if (!throttling) func.apply(context, args);
+      if (finishThrottle) finishThrottle();
+      throttling = true;
+    };
+  };
             		           
                               
                            
                                
               
Returns a function, that, as long as it continues to be invoked, will not
+be triggered. The function will be called after it stops being called for
+N milliseconds.
             		                            
  _.debounce = function(func, wait) {
     var timeout;
     return function() {
       var context = this, args = arguments;
@@ -345,17 +377,10 @@ cleared.
             
                            
timeout = null;
         func.apply(context, args);
       };
-      if (debounce) clearTimeout(timeout);
-      if (debounce || !timeout) timeout = setTimeout(throttler, wait);
+      clearTimeout(timeout);
+      timeout = setTimeout(throttler, wait);
     };
-  };
             		           
                               
                            
                                
               
Returns a function, that, when invoked, will only be triggered at most once
-during a given window of time.
             		                            
  _.throttle = function(func, wait) {
-    return limit(func, wait, false);
-  };
             		           
                               
                            
                                
               
Returns a function, that, as long as it continues to be invoked, will not
-be triggered. The function will be called after it stops being called for
-N milliseconds.
             		                            
  _.debounce = function(func, wait) {
-    return limit(func, wait, true);
-  };
             		           
                               
                            
                                
               
Returns a function that will be executed at most one time, no matter how
+  };             
           
                               
                            
                                
               
Returns a function that will be executed at most one time, no matter how
 often you call it. Useful for lazy initialization.
             		                            
  _.once = function(func) {
     var ran = false, memo;
     return function() {
@@ -363,14 +388,14 @@ often you call it. Useful for lazy initialization.
             

         
           
                             
                               
                            
                                
               
Returns the first function passed as an argument to the second,
+  };             
           
                               
                            
                                
               
Returns the first function passed as an argument to the second,
 allowing you to adjust arguments, run code before and after, and
 conditionally execute the original function.
             		                            
  _.wrap = function(func, wrapper) {
     return function() {
       var args = [func].concat(slice.call(arguments));
       return wrapper.apply(this, args);
     };
-  };
             		           
                               
                            
                                
               
Returns a function that is the composition of a list of functions, each
+  };             
           
                               
                            
                                
               
Returns a function that is the composition of a list of functions, each
 consuming the return value of the function that follows.
             		                            
  _.compose = function() {
     var funcs = slice.call(arguments);
     return function() {
@@ -380,84 +405,80 @@ consuming the return value of the function that follows.
             

       
        
                             
                               
                            
                                
               
Returns a function that will only be executed after being called N times.
             		                            
  _.after = function(times, func) {
+  };
             		           
                               
                            
                                
               
Returns a function that will only be executed after being called N times.
             		                            
  _.after = function(times, func) {
     return function() {
       if (--times < 1) { return func.apply(this, arguments); }
     };
-  };
             		           
                               
                            
                                
               
Object Functions
             		                            
             		           
                               
                            
                                
               
Retrieve the names of an object's properties.
+  };             
           
                               
                            
                                
               
Object Functions
             		                            
             		           
                               
                            
                                
               
Retrieve the names of an object's properties.
 Delegates to ECMAScript 5's native Object.keys
             		                            
  _.keys = nativeKeys || function(obj) {
     if (obj !== Object(obj)) throw new TypeError('Invalid object');
     var keys = [];
     for (var key in obj) if (hasOwnProperty.call(obj, key)) keys[keys.length] = key;
     return keys;
-  };
             		           
                               
                            
                                
               
Retrieve the values of an object's properties.
             		                            
  _.values = function(obj) {
+  };
             		           
                               
                            
                                
               
Retrieve the values of an object's properties.
             		                            
  _.values = function(obj) {
     return _.map(obj, _.identity);
-  };
             		           
                               
                            
                                
               
Return a sorted list of the function names available on the object.
+  };             
           
                               
                            
                                
               
Return a sorted list of the function names available on the object.
 Aliased as methods
             		                            
  _.functions = _.methods = function(obj) {
     var names = [];
     for (var key in obj) {
       if (_.isFunction(obj[key])) names.push(key);
     }
     return names.sort();
-  };
             		           
                               
                            
                                
               
Extend a given object with all the properties in passed-in object(s).
             		                            
  _.extend = function(obj) {
+  };
             		           
                               
                            
                                
               
Extend a given object with all the properties in passed-in object(s).
             		                            
  _.extend = function(obj) {
     each(slice.call(arguments, 1), function(source) {
       for (var prop in source) {
         if (source[prop] !== void 0) obj[prop] = source[prop];
       }
     });
     return obj;
-  };
             		           
                               
                            
                                
               
Fill in a given object with default properties.
             		                            
  _.defaults = function(obj) {
+  };
             		           
                               
                            
                                
               
Fill in a given object with default properties.
             		                            
  _.defaults = function(obj) {
     each(slice.call(arguments, 1), function(source) {
       for (var prop in source) {
         if (obj[prop] == null) obj[prop] = source[prop];
       }
     });
     return obj;
-  };
             		           
                               
                            
                                
               
Create a (shallow-cloned) duplicate of an object.
             		                            
  _.clone = function(obj) {
+  };
             		           
                               
                            
                                
               
Create a (shallow-cloned) duplicate of an object.
             		                            
  _.clone = function(obj) {
+    if (!_.isObject(obj)) return obj;
     return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
-  };
             		           
                               
                            
                                
               
Invokes interceptor with the obj, and then returns obj.
+  };             
           
                               
                            
                                
               
Invokes interceptor with the obj, and then returns obj.
 The primary purpose of this method is to "tap into" a method chain, in
 order to perform operations on intermediate results within the chain.
             		                            
  _.tap = function(obj, interceptor) {
     interceptor(obj);
     return obj;
-  };
             		           
                               
                            
                                
               
Internal recursive comparison function.
             		                            
  function eq(a, b, stack) {
             		           
                               
                            
                                
               
Identical objects are equal. 0 === -0, but they aren't identical.
-See the Harmony egal proposal: http://wiki.ecmascript.org/doku.php?id=harmony:egal.
             		                            
    if (a === b) return a !== 0 || 1 / a == 1 / b;
             		           
                               
                            
                                
               
A strict comparison is necessary because null == undefined.
             		                            
    if (a == null) return a === b;
             		           
                               
                            
                                
               
Compare object types.
             		                            
    var typeA = typeof a;
-    if (typeA != typeof b) return false;
             		           
                               
                            
                                
               
Optimization; ensure that both values are truthy or falsy.
             		                            
    if (!a != !b) return false;
             		           
                               
                            
                                
               
NaN values are equal.
             		                            
    if (_.isNaN(a)) return _.isNaN(b);
             		           
                               
                            
                                
               
Compare string objects by value.
             		                            
    var isStringA = _.isString(a), isStringB = _.isString(b);
-    if (isStringA || isStringB) return isStringA && isStringB && String(a) == String(b);
             		           
                               
                            
                                
               
Compare number objects by value.
             		                            
    var isNumberA = _.isNumber(a), isNumberB = _.isNumber(b);
-    if (isNumberA || isNumberB) return isNumberA && isNumberB && +a == +b;
             		           
                               
                            
                                
               
Compare boolean objects by value. The value of true is 1; the value of false is 0.
             		                            
    var isBooleanA = _.isBoolean(a), isBooleanB = _.isBoolean(b);
-    if (isBooleanA || isBooleanB) return isBooleanA && isBooleanB && +a == +b;
             		           
                               
                            
                                
               
Compare dates by their millisecond values.
             		                            
    var isDateA = _.isDate(a), isDateB = _.isDate(b);
-    if (isDateA || isDateB) return isDateA && isDateB && a.getTime() == b.getTime();
             		           
                               
                            
                                
               
Compare RegExps by their source patterns and flags.
             		                            
    var isRegExpA = _.isRegExp(a), isRegExpB = _.isRegExp(b);
-    if (isRegExpA || isRegExpB) {
             		           
                               
                            
                                
               
Ensure commutative equality for RegExps.
             		                            
      return isRegExpA && isRegExpB &&
+  };
             		           
                               
                            
                                
               
Internal recursive comparison function.
             		                            
  function eq(a, b, stack) {
             		           
                               
                            
                                
               
Identical objects are equal. 0 === -0, but they aren't identical.
+See the Harmony egal proposal: http://wiki.ecmascript.org/doku.php?id=harmony:egal.
             		                            
    if (a === b) return a !== 0 || 1 / a == 1 / b;
             		           
                               
                            
                                
               
A strict comparison is necessary because null == undefined.
             		                            
    if ((a == null) || (b == null)) return a === b;
             		           
                               
                            
                                
               
Unwrap any wrapped objects.
             		                            
    if (a._chain) a = a._wrapped;
+    if (b._chain) b = b._wrapped;
             		           
                               
                            
                                
               
Invoke a custom isEqual method if one is provided.
             		                            
    if (_.isFunction(a.isEqual)) return a.isEqual(b);
+    if (_.isFunction(b.isEqual)) return b.isEqual(a);
             		           
                               
                            
                                
               
Compare object types.
             		                            
    var typeA = typeof a;
+    if (typeA != typeof b) return false;
             		           
                               
                            
                                
               
Optimization; ensure that both values are truthy or falsy.
             		                            
    if (!a != !b) return false;
             		           
                               
                            
                                
               
NaN values are equal.
             		                            
    if (_.isNaN(a)) return _.isNaN(b);
             		           
                               
                            
                                
               
Compare string objects by value.
             		                            
    var isStringA = _.isString(a), isStringB = _.isString(b);
+    if (isStringA || isStringB) return isStringA && isStringB && String(a) == String(b);
             		           
                               
                            
                                
               
Compare number objects by value.
             		                            
    var isNumberA = _.isNumber(a), isNumberB = _.isNumber(b);
+    if (isNumberA || isNumberB) return isNumberA && isNumberB && +a == +b;
             		           
                               
                            
                                
               
Compare boolean objects by value. The value of true is 1; the value of false is 0.
             		                            
    var isBooleanA = _.isBoolean(a), isBooleanB = _.isBoolean(b);
+    if (isBooleanA || isBooleanB) return isBooleanA && isBooleanB && +a == +b;
             		           
                               
                            
                                
               
Compare dates by their millisecond values.
             		                            
    var isDateA = _.isDate(a), isDateB = _.isDate(b);
+    if (isDateA || isDateB) return isDateA && isDateB && a.getTime() == b.getTime();
             		           
                               
                            
                                
               
Compare RegExps by their source patterns and flags.
             		                            
    var isRegExpA = _.isRegExp(a), isRegExpB = _.isRegExp(b);
+    if (isRegExpA || isRegExpB) {
             		           
                               
                            
                                
               
Ensure commutative equality for RegExps.
             		                            
      return isRegExpA && isRegExpB &&
              a.source == b.source &&
              a.global == b.global &&
              a.multiline == b.multiline &&
              a.ignoreCase == b.ignoreCase;
-    }
             		           
                               
                            
                                
               
Ensure that both values are objects.
             		                            
    if (typeA != 'object') return false;
             		           
                               
                            
                                
               
Unwrap any wrapped objects.
             		                            
    if (a._chain) a = a._wrapped;
-    if (b._chain) b = b._wrapped;
             		           
                               
                            
                                
               
Invoke a custom isEqual method if one is provided.
             		                            
    if (_.isFunction(a.isEqual)) return a.isEqual(b);
             		           
                               
                            
                                
               
Assume equality for cyclic structures. The algorithm for detecting cyclic structures is
-adapted from ES 5.1 section 15.12.3, abstract operation JO.
             		                            
    var length = stack.length;
-    while (length--) {
             		           
                               
                            
                                
               
Linear search. Performance is inversely proportional to the number of unique nested
-structures.
             		                            
      if (stack[length] == a) return true;
-    }
             		           
                               
                            
                                
               
Add the first object to the stack of traversed objects.
             		                            
    stack.push(a);
-    var size = 0, result = true;
-    if (a.length === +a.length || b.length === +b.length) {
             		           
                               
                            
                                
               
Compare object lengths to determine if a deep comparison is necessary.
             		                            
      size = a.length;
-      result = size == b.length;
-      if (result) {
             		           
                               
                            
                                
               
Deep compare array-like object contents, ignoring non-numeric properties.
             		                            
        while (size--) {
             		           
                               
                            
                                
               
Ensure commutative equality for sparse arrays.
             		                            
          if (!(result = size in a == size in b && eq(a[size], b[size], stack))) break;
-        }
+    }
             		           
                               
                            
                                
               
Ensure that both values are objects.
             		                            
    if (typeA != 'object') return false;
             		           
                               
                            
                                
               
Arrays or Arraylikes with different lengths are not equal.
             		                            
    if (a.length !== b.length) return false;
             		           
                               
                            
                                
               
Objects with different constructors are not equal.
             		                            
    if (a.constructor !== b.constructor) return false;
             		           
                               
                            
                                
               
Assume equality for cyclic structures. The algorithm for detecting cyclic
+structures is adapted from ES 5.1 section 15.12.3, abstract operation JO.
             		                            
    var length = stack.length;
+    while (length--) {
             		           
                               
                            
                                
               
Linear search. Performance is inversely proportional to the number of
+unique nested structures.
             		                            
      if (stack[length] == a) return true;
+    }
             		           
                               
                            
                                
               
Add the first object to the stack of traversed objects.
             		                            
    stack.push(a);
+    var size = 0, result = true;
             		           
                               
                            
                                
               
Deep compare objects.
             		                            
    for (var key in a) {
+      if (hasOwnProperty.call(a, key)) {
             		           
                               
                            
                                
               
Count the expected number of properties.
             		                            
        size++;
             		           
                               
                            
                                
               
Deep compare each member.
             		                            
        if (!(result = hasOwnProperty.call(b, key) && eq(a[key], b[key], stack))) break;
       }
-    } else {
             		           
                               
                            
                                
               
Deep compare objects.
             		                            
      for (var key in a) {
-        if (hasOwnProperty.call(a, key)) {
             		           
                               
                            
                                
               
Count the expected number of properties.
             		                            
          size++;
             		           
                               
                            
                                
               
Deep compare each member.
             		                            
          if (!(result = hasOwnProperty.call(b, key) && eq(a[key], b[key], stack))) break;
-        }
-      }
             		           
                               
                            
                                
               
Ensure that both objects contain the same number of properties.
             		                            
      if (result) {
-        for (key in b) {
-          if (hasOwnProperty.call(b, key) && !size--) break;
-        }
-        result = !size;
+    }
             		           
                               
                            
                                
               
Ensure that both objects contain the same number of properties.
             		                            
    if (result) {
+      for (key in b) {
+        if (hasOwnProperty.call(b, key) && !size--) break;
       }
+      result = !size;
     }
             		           
                               
                            
                                
               
Remove the first object from the stack of traversed objects.
             		                            
    stack.pop();
     return result;
   }
             		           
                               
                            
                                
               
Perform a deep comparison to check if two objects are equal.
             		                            
  _.isEqual = function(a, b) {
     return eq(a, b, []);
-  };
             		           
                               
                            
                                
               
Is a given array or object empty?
             		                            
  _.isEmpty = function(obj) {
+  };
             		           
                               
                            
                                
               
Is a given array, string, or object empty?
+An "empty" object has no enumerable own-properties.
             		                            
  _.isEmpty = function(obj) {
     if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
     for (var key in obj) if (hasOwnProperty.call(obj, key)) return false;
     return true;
@@ -465,56 +486,60 @@ structures.
             
                            return !!(obj && obj.nodeType == 1);
   };                        
                               
                            
                                
               
Is a given value an array?
 Delegates to ECMA5's native Array.isArray
             		                            
  _.isArray = nativeIsArray || function(obj) {
-    return toString.call(obj) === '[object Array]';
+    return toString.call(obj) == '[object Array]';
   };
             		           
                               
                            
                                
               
Is a given variable an object?
             		                            
  _.isObject = function(obj) {
     return obj === Object(obj);
-  };
             		           
                               
                            
                                
               
Is a given variable an arguments object?
             		                            
  _.isArguments = function(obj) {
-    return !!(obj && hasOwnProperty.call(obj, 'callee'));
-  };
             		           
                               
                            
                                
               
Is a given value a function?
             		                            
  _.isFunction = function(obj) {
-    return !!(obj && obj.constructor && obj.call && obj.apply);
+  };
             		           
                               
                            
                                
               
Is a given variable an arguments object?
             		                            
  if (toString.call(arguments) == '[object Arguments]') {
+    _.isArguments = function(obj) {
+      return toString.call(obj) == '[object Arguments]';
+    };
+  } else {
+    _.isArguments = function(obj) {
+      return !!(obj && hasOwnProperty.call(obj, 'callee'));
+    };
+  }
             		           
                               
                            
                                
               
Is a given value a function?
             		                            
  _.isFunction = function(obj) {
+    return toString.call(obj) == '[object Function]';
   };
             		           
                               
                            
                                
               
Is a given value a string?
             		                            
  _.isString = function(obj) {
-    return !!(obj === '' || (obj && obj.charCodeAt && obj.substr));
+    return toString.call(obj) == '[object String]';
   };
             		           
                               
                            
                                
               
Is a given value a number?
             		                            
  _.isNumber = function(obj) {
-    return !!(obj === 0 || (obj && obj.toExponential && obj.toFixed));
-  };
             		           
                               
                            
                                
               
Is the given value NaN? NaN happens to be the only value in JavaScript
-that does not equal itself.
             		                            
  _.isNaN = function(obj) {
-    return obj !== obj;
-  };
             		           
                               
                            
                                
               
Is a given value a boolean?
             		                            
  _.isBoolean = function(obj) {
+    return toString.call(obj) == '[object Number]';
+  };
             		           
                               
                            
                                
               
Is the given value NaN?
             		                            
  _.isNaN = function(obj) {
             		           
                               
                            
                                
               
NaN is the only value for which === is not reflexive.
             		                            
    return obj !== obj;
+  };
             		           
                               
                            
                                
               
Is a given value a boolean?
             		                            
  _.isBoolean = function(obj) {
     return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
-  };
             		           
                               
                            
                                
               
Is a given value a date?
             		                            
  _.isDate = function(obj) {
-    return !!(obj && obj.getTimezoneOffset && obj.setUTCFullYear);
-  };
             		           
                               
                            
                                
               
Is the given value a regular expression?
             		                            
  _.isRegExp = function(obj) {
-    return !!(obj && obj.test && obj.exec && (obj.ignoreCase || obj.ignoreCase === false));
-  };
             		           
                               
                            
                                
               
Is a given value equal to null?
             		                            
  _.isNull = function(obj) {
+  };
             		           
                               
                            
                                
               
Is a given value a date?
             		                            
  _.isDate = function(obj) {
+    return toString.call(obj) == '[object Date]';
+  };
             		           
                               
                            
                                
               
Is the given value a regular expression?
             		                            
  _.isRegExp = function(obj) {
+    return toString.call(obj) == '[object RegExp]';
+  };
             		           
                               
                            
                                
               
Is a given value equal to null?
             		                            
  _.isNull = function(obj) {
     return obj === null;
-  };
             		           
                               
                            
                                
               
Is a given variable undefined?
             		                            
  _.isUndefined = function(obj) {
+  };
             		           
                               
                            
                                
               
Is a given variable undefined?
             		                            
  _.isUndefined = function(obj) {
     return obj === void 0;
-  };
             		           
                               
                            
                                
               
Utility Functions
             		                            
             		           
                               
                            
                                
               
Run Underscore.js in noConflict mode, returning the _ variable to its
+  };             
           
                               
                            
                                
               
Utility Functions
             		                            
             		           
                               
                            
                                
               
Run Underscore.js in noConflict mode, returning the _ variable to its
 previous owner. Returns a reference to the Underscore object.
             		                            
  _.noConflict = function() {
     root._ = previousUnderscore;
     return this;
-  };
             		           
                               
                            
                                
               
Keep the identity function around for default iterators.
             		                            
  _.identity = function(value) {
+  };
             		           
                               
                            
                                
               
Keep the identity function around for default iterators.
             		                            
  _.identity = function(value) {
     return value;
-  };
             		           
                               
                            
                                
               
Run a function n times.
             		                            
  _.times = function (n, iterator, context) {
+  };
             		           
                               
                            
                                
               
Run a function n times.
             		                            
  _.times = function (n, iterator, context) {
     for (var i = 0; i < n; i++) iterator.call(context, i);
-  };
             		           
                               
                            
                                
               
Escape a string for HTML interpolation.
             		                            
  _.escape = function(string) {
+  };
             		           
                               
                            
                                
               
Escape a string for HTML interpolation.
             		                            
  _.escape = function(string) {
     return (''+string).replace(/&(?!\w+;|#\d+;|#x[\da-f]+;)/gi, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&#x27;').replace(/\//g,'&#x2F;');
-  };
             		           
                               
                            
                                
               
Add your own custom functions to the Underscore object, ensuring that
+  };             
           
                               
                            
                                
               
Add your own custom functions to the Underscore object, ensuring that
 they're correctly added to the OOP wrapper as well.
             		                            
  _.mixin = function(obj) {
     each(_.functions(obj), function(name){
       addToWrapper(name, _[name] = obj[name]);
     });
-  };
             		           
                               
                            
                                
               
Generate a unique integer id (unique within the entire client session).
+  };             
           
                               
                            
                                
               
Generate a unique integer id (unique within the entire client session).
 Useful for temporary DOM ids.
             		                            
  var idCounter = 0;
   _.uniqueId = function(prefix) {
     var id = idCounter++;
     return prefix ? prefix + id : id;
-  };
             		           
                               
                            
                                
               
By default, Underscore uses ERB-style template delimiters, change the
+  };             
           
                               
                            
                                
               
By default, Underscore uses ERB-style template delimiters, change the
 following template settings to use alternative delimiters.
             		                            
  _.templateSettings = {
     evaluate    : /<%([\s\S]+?)%>/g,
     interpolate : /<%=([\s\S]+?)%>/g,
     escape      : /<%-([\s\S]+?)%>/g
-  };
             		           
                               
                            
                                
               
JavaScript micro-templating, similar to John Resig's implementation.
+  };             
           
                               
                            
                                
               
JavaScript micro-templating, similar to John Resig's implementation.
 Underscore templating handles arbitrary delimiters, preserves whitespace,
 and correctly escapes quotes within interpolated code.
             		                            
  _.template = function(str, data) {
     var c  = _.templateSettings;
@@ -538,31 +563,31 @@ and correctly escapes quotes within interpolated code.
             

           
          
                                  
                               
                            
                                
               
The OOP Wrapper
             		                            
             		           
                               
                            
                                
               
If Underscore is called as a function, it returns a wrapped object that
+  };             
           
                               
                            
                                
               
The OOP Wrapper
             		                            
             		           
                               
                            
                                
               
If Underscore is called as a function, it returns a wrapped object that
 can be used OO-style. This wrapper holds altered versions of all the
-underscore functions. Wrapped objects may be chained.
             		                            
  var wrapper = function(obj) { this._wrapped = obj; };
             		           
                               
                            
                                
               
Expose wrapper.prototype as _.prototype
             		                            
  _.prototype = wrapper.prototype;
             		           
                               
                            
                                
               
Helper function to continue chaining intermediate results.
             		                            
  var result = function(obj, chain) {
+underscore functions. Wrapped objects may be chained.
             
                            
  var wrapper = function(obj) { this._wrapped = obj; };
             		           
                               
                            
                                
               
Expose wrapper.prototype as _.prototype
             		                            
  _.prototype = wrapper.prototype;
             		           
                               
                            
                                
               
Helper function to continue chaining intermediate results.
             		                            
  var result = function(obj, chain) {
     return chain ? _(obj).chain() : obj;
-  };
             		           
                               
                            
                                
               
A method to easily add functions to the OOP wrapper.
             		                            
  var addToWrapper = function(name, func) {
+  };
             		           
                               
                            
                                
               
A method to easily add functions to the OOP wrapper.
             		                            
  var addToWrapper = function(name, func) {
     wrapper.prototype[name] = function() {
       var args = slice.call(arguments);
       unshift.call(args, this._wrapped);
       return result(func.apply(_, args), this._chain);
     };
-  };
             		           
                               
                            
                                
               
Add all of the Underscore functions to the wrapper object.
             		                            
  _.mixin(_);
             		           
                               
                            
                                
               
Add all mutator Array functions to the wrapper.
             		                            
  each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
+  };
             		           
                               
                            
                                
               
Add all of the Underscore functions to the wrapper object.
             		                            
  _.mixin(_);
             		           
                               
                            
                                
               
Add all mutator Array functions to the wrapper.
             		                            
  each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
     var method = ArrayProto[name];
     wrapper.prototype[name] = function() {
       method.apply(this._wrapped, arguments);
       return result(this._wrapped, this._chain);
     };
-  });
             		           
                               
                            
                                
               
Add all accessor Array functions to the wrapper.
             		                            
  each(['concat', 'join', 'slice'], function(name) {
+  });
             		           
                               
                            
                                
               
Add all accessor Array functions to the wrapper.
             		                            
  each(['concat', 'join', 'slice'], function(name) {
     var method = ArrayProto[name];
     wrapper.prototype[name] = function() {
       return result(method.apply(this._wrapped, arguments), this._chain);
     };
-  });
             		           
                               
                            
                                
               
Start chaining a wrapped Underscore object.
             		                            
  wrapper.prototype.chain = function() {
+  });
             		           
                               
                            
                                
               
Start chaining a wrapped Underscore object.
             		                            
  wrapper.prototype.chain = function() {
     this._chain = true;
     return this;
-  };
             		           
                               
                            
                                
               
Extracts the result from a wrapped and chained object.
             		                            
  wrapper.prototype.value = function() {
+  };
             		           
                               
                            
                                
               
Extracts the result from a wrapped and chained object.
             		                            
  wrapper.prototype.value = function() {
     return this._wrapped;
   };
 
diff --git a/index.html b/index.html
index 1b4f4313f..8c8e7c914 100644
--- a/index.html
+++ b/index.html
@@ -126,11 +126,11 @@
 
     
-        
-        
+        
+        
-        
+        

       
Development Version (1.2.0)32kb, Uncompressed with CommentsDevelopment Version (1.2.1)33kb, Uncompressed with Comments
       

       
Production Version (1.2.0)Production Version (1.2.1)
         < 4kb, Minified and Gzipped
       

     

@@ -454,11 +454,16 @@ _.sortBy([1, 2, 3, 4, 5, 6], function(num){ return Math.sin(num); });
         groupBy_.groupBy(list, iterator)
         

         Splits a collection into sets, grouped by the result of running each
-        value through iterator.
+        value through iterator. If iterator is a string instead of
+        a function, groups by the property named by iterator on each of
+        the values.
       

       
 _.groupBy([1.3, 2.1, 2.4], function(num){ return Math.floor(num); });
 => {1: [1.3], 2: [2.1, 2.4]}
+
+_.groupBy(['one', 'two', 'three'], 'length');
+=> {3: ["one", "two"], 5: ["three"]}
 

 
       

@@ -1265,26 +1270,6 @@ _([1, 2, 3]).value();
 => [1, 2, 3]
 

 
-      
Duck Typing

-
-      

-        The isType (isArray, isFunction, isString ...) family of type-checking
-        functions use property detection to do their work, which, although
-        orders of magnitude faster than the alternative, isn't entirely safe when dealing
-        with objects that are used as hashes, where arbitrary strings are being
-        set for the keys. It's entirely possible for an object to masquerade as
-        another type, if you're setting properties with names like "concat" and
-        "charCodeAt". So be aware.
-      

-      
-      

-        In a similar fashion, _.each and all of the other functions 
-        based on it are designed to be able to iterate over any Array-like
-        JavaScript object, including arguments, NodeLists, and more.
-        Passing hash-like objects with a numeric length key won't work.
-      

-
-
       
Links & Suggested Reading

 
       

@@ -1343,6 +1328,45 @@ _([1, 2, 3]).value();
 
       
Change Log

       
+      

+        1.2.1 — Oct. 24, 2011

+        
    
+          
  • 
+            Several important bug fixes for _.isEqual, which should now 
+            do better on mutated Arrays, and on non-Array objects with 
+            length properties. (#329)
+          
    • 
+          
  • 
+            jrburke contributed Underscore exporting for AMD module loaders,
+            and tonylukasavage for Appcelerator Titanium. 
+            (#335, #338)
+          
    • 
+          
  • 
+            You can now _.groupBy(list, 'property') as a shortcut for
+            grouping values by a particular common property.
+          
    • 
+          
  • 
+            _.throttle'd functions now fire immediately upon invocation, 
+            and are rate-limited thereafter (#170, #266).
+          
    • 
+          
  • 
+            Most of the _.is[Type] checks no longer ducktype.
+          
    • 
+          
  • 
+            The _.bind function now also works on constructors, a-la
+            ES5 ... but you would never want to use _.bind on a 
+            constructor function.
+          
    • 
+          
  • 
+            _.clone no longer wraps non-object types in Objects.
+          
    • 
+          
  • 
+            _.find and _.filter are now the preferred names for
+            _.detect and _.select.
+          
    • 
+        

+      

+      
       

         1.2.0 — Oct. 5, 2011

         
    
diff --git a/package.json b/package.json
index eb4eee826..54f839863 100644
--- a/package.json
+++ b/package.json
@@ -8,5 +8,5 @@
   "dependencies"  : [],
   "repository"    : {"type": "git", "url": "git://github.com/documentcloud/underscore.git"},
   "main"          : "underscore.js",
-  "version"       : "1.2.0"
+  "version"       : "1.2.1"
 }
diff --git a/underscore-min.js b/underscore-min.js
index caa773615..ad3756028 100644
--- a/underscore-min.js
+++ b/underscore-min.js
@@ -1,29 +1,30 @@
-// Underscore.js 1.2.0
+// Underscore.js 1.2.1
 // (c) 2011 Jeremy Ashkenas, DocumentCloud Inc.
 // Underscore is freely distributable under the MIT license.
 // Portions of Underscore are inspired or borrowed from Prototype,
 // Oliver Steele's Functional, and John Resig's Micro-Templating.
 // For all details and documentation:
 // http://documentcloud.github.com/underscore
-(function(){function q(a,c,d){if(a===c)return a!==0||1/a==1/c;if(a==null)return a===c;var e=typeof a;if(e!=typeof c)return false;if(!a!=!c)return false;if(b.isNaN(a))return b.isNaN(c);var f=b.isString(a),g=b.isString(c);if(f||g)return f&&g&&String(a)==String(c);f=b.isNumber(a);g=b.isNumber(c);if(f||g)return f&&g&&+a==+c;f=b.isBoolean(a);g=b.isBoolean(c);if(f||g)return f&&g&&+a==+c;f=b.isDate(a);g=b.isDate(c);if(f||g)return f&&g&&a.getTime()==c.getTime();f=b.isRegExp(a);g=b.isRegExp(c);if(f||g)return f&&
-g&&a.source==c.source&&a.global==c.global&&a.multiline==c.multiline&&a.ignoreCase==c.ignoreCase;if(e!="object")return false;if(a._chain)a=a._wrapped;if(c._chain)c=c._wrapped;if(b.isFunction(a.isEqual))return a.isEqual(c);for(e=d.length;e--;)if(d[e]==a)return true;d.push(a);e=0;f=true;if(a.length===+a.length||c.length===+c.length){if(e=a.length,f=e==c.length)for(;e--;)if(!(f=e in a==e in c&&q(a[e],c[e],d)))break}else{for(var h in a)if(l.call(a,h)&&(e++,!(f=l.call(c,h)&&q(a[h],c[h],d))))break;if(f){for(h in c)if(l.call(c,
-h)&&!e--)break;f=!e}}d.pop();return f}var r=this,F=r._,n={},k=Array.prototype,o=Object.prototype,i=k.slice,G=k.unshift,u=o.toString,l=o.hasOwnProperty,v=k.forEach,w=k.map,x=k.reduce,y=k.reduceRight,z=k.filter,A=k.every,B=k.some,p=k.indexOf,C=k.lastIndexOf,o=Array.isArray,H=Object.keys,s=Function.prototype.bind,b=function(a){return new m(a)};typeof module!=="undefined"&&module.exports?(module.exports=b,b._=b):r._=b;b.VERSION="1.2.0";var j=b.each=b.forEach=function(a,c,b){if(a!=null)if(v&&a.forEach===
-v)a.forEach(c,b);else if(a.length===+a.length)for(var e=0,f=a.length;e=e.computed&&(e={value:a,computed:b})});return e.value};b.min=function(a,c,d){if(!c&&b.isArray(a))return Math.min.apply(Math,a);if(!c&&b.isEmpty(a))return Infinity;var e={computed:Infinity};j(a,function(a,b,h){b=c?c.call(d,a,b,h):a;bd?1:0}),"value")};b.groupBy=function(a,b){var d={};j(a,function(a,f){var g=b(a,f);(d[g]||(d[g]=[])).push(a)});return d};b.sortedIndex=function(a,c,d){d||(d=b.identity);for(var e=0,f=a.length;e>1;d(a[g])=0})})};
-b.difference=function(a,c){return b.filter(a,function(a){return!b.include(c,a)})};b.zip=function(){for(var a=i.call(arguments),c=b.max(b.pluck(a,"length")),d=Array(c),e=0;e=0;d--)b=[a[d].apply(this,b)];return b[0]}};b.after=function(a,b){return function(){if(--a<1)return b.apply(this,
-arguments)}};b.keys=H||function(a){if(a!==Object(a))throw new TypeError("Invalid object");var b=[],d;for(d in a)l.call(a,d)&&(b[b.length]=d);return b};b.values=function(a){return b.map(a,b.identity)};b.functions=b.methods=function(a){var c=[],d;for(d in a)b.isFunction(a[d])&&c.push(d);return c.sort()};b.extend=function(a){j(i.call(arguments,1),function(b){for(var d in b)b[d]!==void 0&&(a[d]=b[d])});return a};b.defaults=function(a){j(i.call(arguments,1),function(b){for(var d in b)a[d]==null&&(a[d]=
-b[d])});return a};b.clone=function(a){return b.isArray(a)?a.slice():b.extend({},a)};b.tap=function(a,b){b(a);return a};b.isEqual=function(a,b){return q(a,b,[])};b.isEmpty=function(a){if(b.isArray(a)||b.isString(a))return a.length===0;for(var c in a)if(l.call(a,c))return false;return true};b.isElement=function(a){return!!(a&&a.nodeType==1)};b.isArray=o||function(a){return u.call(a)==="[object Array]"};b.isObject=function(a){return a===Object(a)};b.isArguments=function(a){return!(!a||!l.call(a,"callee"))};
-b.isFunction=function(a){return!(!a||!a.constructor||!a.call||!a.apply)};b.isString=function(a){return!!(a===""||a&&a.charCodeAt&&a.substr)};b.isNumber=function(a){return!!(a===0||a&&a.toExponential&&a.toFixed)};b.isNaN=function(a){return a!==a};b.isBoolean=function(a){return a===true||a===false||u.call(a)=="[object Boolean]"};b.isDate=function(a){return!(!a||!a.getTimezoneOffset||!a.setUTCFullYear)};b.isRegExp=function(a){return!(!a||!a.test||!a.exec||!(a.ignoreCase||a.ignoreCase===false))};b.isNull=
-function(a){return a===null};b.isUndefined=function(a){return a===void 0};b.noConflict=function(){r._=F;return this};b.identity=function(a){return a};b.times=function(a,b,d){for(var e=0;e/g,">").replace(/"/g,""").replace(/'/g,"'").replace(/\//g,"/")};b.mixin=function(a){j(b.functions(a),function(c){I(c,b[c]=a[c])})};var J=0;b.uniqueId=function(a){var b=
-J++;return a?a+b:b};b.templateSettings={evaluate:/<%([\s\S]+?)%>/g,interpolate:/<%=([\s\S]+?)%>/g,escape:/<%-([\s\S]+?)%>/g};b.template=function(a,c){var d=b.templateSettings,d="var __p=[],print=function(){__p.push.apply(__p,arguments);};with(obj||{}){__p.push('"+a.replace(/\\/g,"\\\\").replace(/'/g,"\\'").replace(d.escape,function(a,b){return"',_.escape("+b.replace(/\\'/g,"'")+"),'"}).replace(d.interpolate,function(a,b){return"',"+b.replace(/\\'/g,"'")+",'"}).replace(d.evaluate||null,function(a,
-b){return"');"+b.replace(/\\'/g,"'").replace(/[\r\n\t]/g," ")+"__p.push('"}).replace(/\r/g,"\\r").replace(/\n/g,"\\n").replace(/\t/g,"\\t")+"');}return __p.join('');",d=new Function("obj",d);return c?d(c):d};var m=function(a){this._wrapped=a};b.prototype=m.prototype;var t=function(a,c){return c?b(a).chain():a},I=function(a,c){m.prototype[a]=function(){var a=i.call(arguments);G.call(a,this._wrapped);return t(c.apply(b,a),this._chain)}};b.mixin(b);j("pop,push,reverse,shift,sort,splice,unshift".split(","),
-function(a){var b=k[a];m.prototype[a]=function(){b.apply(this._wrapped,arguments);return t(this._wrapped,this._chain)}});j(["concat","join","slice"],function(a){var b=k[a];m.prototype[a]=function(){return t(b.apply(this._wrapped,arguments),this._chain)}});m.prototype.chain=function(){this._chain=true;return this};m.prototype.value=function(){return this._wrapped}})();
+(function(){function u(a,c,d){if(a===c)return a!==0||1/a==1/c;if(a==null||c==null)return a===c;if(a._chain)a=a._wrapped;if(c._chain)c=c._wrapped;if(b.isFunction(a.isEqual))return a.isEqual(c);if(b.isFunction(c.isEqual))return c.isEqual(a);var e=typeof a;if(e!=typeof c)return false;if(!a!=!c)return false;if(b.isNaN(a))return b.isNaN(c);var g=b.isString(a),f=b.isString(c);if(g||f)return g&&f&&String(a)==String(c);g=b.isNumber(a);f=b.isNumber(c);if(g||f)return g&&f&&+a==+c;g=b.isBoolean(a);f=b.isBoolean(c);
+if(g||f)return g&&f&&+a==+c;g=b.isDate(a);f=b.isDate(c);if(g||f)return g&&f&&a.getTime()==c.getTime();g=b.isRegExp(a);f=b.isRegExp(c);if(g||f)return g&&f&&a.source==c.source&&a.global==c.global&&a.multiline==c.multiline&&a.ignoreCase==c.ignoreCase;if(e!="object")return false;if(a.length!==c.length)return false;if(a.constructor!==c.constructor)return false;for(e=d.length;e--;)if(d[e]==a)return true;d.push(a);var e=0,g=true,h;for(h in a)if(m.call(a,h)&&(e++,!(g=m.call(c,h)&&u(a[h],c[h],d))))break;if(g){for(h in c)if(m.call(c,
+h)&&!e--)break;g=!e}d.pop();return g}var r=this,F=r._,o={},k=Array.prototype,p=Object.prototype,i=k.slice,G=k.unshift,l=p.toString,m=p.hasOwnProperty,v=k.forEach,w=k.map,x=k.reduce,y=k.reduceRight,z=k.filter,A=k.every,B=k.some,q=k.indexOf,C=k.lastIndexOf,p=Array.isArray,H=Object.keys,s=Function.prototype.bind,b=function(a){return new n(a)};if(typeof exports!=="undefined"){if(typeof module!=="undefined"&&module.exports)exports=module.exports=b;exports._=b}else typeof define==="function"&&define.amd?
+define("underscore",function(){return b}):r._=b;b.VERSION="1.2.1";var j=b.each=b.forEach=function(a,c,b){if(a!=null)if(v&&a.forEach===v)a.forEach(c,b);else if(a.length===+a.length)for(var e=0,g=a.length;e=e.computed&&(e={value:a,computed:b})});return e.value};b.min=function(a,c,d){if(!c&&b.isArray(a))return Math.min.apply(Math,a);if(!c&&b.isEmpty(a))return Infinity;var e={computed:Infinity};j(a,function(a,b,h){b=c?c.call(d,a,b,h):a;bd?1:0}),"value")};b.groupBy=function(a,c){var d={},e=b.isFunction(c)?c:function(a){return a[c]};j(a,function(a,b){var c=e(a,b);(d[c]||(d[c]=[])).push(a)});return d};b.sortedIndex=function(a,c,d){d||(d=b.identity);for(var e=0,g=a.length;e<
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+var b=[],d;for(d in a)m.call(a,d)&&(b[b.length]=d);return b};b.values=function(a){return b.map(a,b.identity)};b.functions=b.methods=function(a){var c=[],d;for(d in a)b.isFunction(a[d])&&c.push(d);return c.sort()};b.extend=function(a){j(i.call(arguments,1),function(b){for(var d in b)b[d]!==void 0&&(a[d]=b[d])});return a};b.defaults=function(a){j(i.call(arguments,1),function(b){for(var d in b)a[d]==null&&(a[d]=b[d])});return a};b.clone=function(a){return!b.isObject(a)?a:b.isArray(a)?a.slice():b.extend({},
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+void 0};b.noConflict=function(){r._=F;return this};b.identity=function(a){return a};b.times=function(a,b,d){for(var e=0;e/g,">").replace(/"/g,""").replace(/'/g,"'").replace(/\//g,"/")};b.mixin=function(a){j(b.functions(a),function(c){I(c,b[c]=a[c])})};var J=0;b.uniqueId=function(a){var b=J++;return a?a+b:b};b.templateSettings={evaluate:/<%([\s\S]+?)%>/g,
+interpolate:/<%=([\s\S]+?)%>/g,escape:/<%-([\s\S]+?)%>/g};b.template=function(a,c){var d=b.templateSettings,d="var __p=[],print=function(){__p.push.apply(__p,arguments);};with(obj||{}){__p.push('"+a.replace(/\\/g,"\\\\").replace(/'/g,"\\'").replace(d.escape,function(a,b){return"',_.escape("+b.replace(/\\'/g,"'")+"),'"}).replace(d.interpolate,function(a,b){return"',"+b.replace(/\\'/g,"'")+",'"}).replace(d.evaluate||null,function(a,b){return"');"+b.replace(/\\'/g,"'").replace(/[\r\n\t]/g," ")+"__p.push('"}).replace(/\r/g,
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+this._chain)}});j(["concat","join","slice"],function(a){var b=k[a];n.prototype[a]=function(){return t(b.apply(this._wrapped,arguments),this._chain)}});n.prototype.chain=function(){this._chain=true;return this};n.prototype.value=function(){return this._wrapped}})();
diff --git a/underscore.js b/underscore.js
index 5470fa6b3..ab4c26094 100644
--- a/underscore.js
+++ b/underscore.js
@@ -1,4 +1,4 @@
-//     Underscore.js 1.2.0
+//     Underscore.js 1.2.1
 //     (c) 2011 Jeremy Ashkenas, DocumentCloud Inc.
 //     Underscore is freely distributable under the MIT license.
 //     Portions of Underscore are inspired or borrowed from Prototype,
@@ -67,7 +67,7 @@
   }
 
   // Current version.
-  _.VERSION = '1.2.0';
+  _.VERSION = '1.2.1';
 
   // Collection Functions
   // --------------------