Update vendor/underscore.

Former-commit-id: d1cca79a4f6732ee8cd48dd4574041b4ebe19edf

vendor/underscore/underscore.js

@@ -96,7 +96,7 @@
     if (obj == null) return results;
     if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
     each(obj, function(value, index, list) {
-      results[results.length] = iterator.call(context, value, index, list);
+      results.push(iterator.call(context, value, index, list));
     });
     return results;
   };
@@ -171,7 +171,7 @@
     if (obj == null) return results;
     if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context);
     each(obj, function(value, index, list) {
-      if (iterator.call(context, value, index, list)) results[results.length] = value;
+      if (iterator.call(context, value, index, list)) results.push(value);
     });
     return results;
   };
@@ -238,7 +238,7 @@
   // Convenience version of a common use case of `filter`: selecting only objects
   // containing specific `key:value` pairs.
   _.where = function(obj, attrs, first) {
-    if (_.isEmpty(attrs)) return first ? null : [];
+    if (_.isEmpty(attrs)) return first ? void 0 : [];
     return _[first ? 'find' : 'filter'](obj, function(value) {
       for (var key in attrs) {
         if (attrs[key] !== value[key]) return false;
@@ -324,7 +324,7 @@
   // An internal function used for aggregate "group by" operations.
   var group = function(obj, value, context, behavior) {
     var result = {};
-    var iterator = lookupIterator(value || _.identity);
+    var iterator = lookupIterator(value == null ? _.identity : value);
     each(obj, function(value, index) {
       var key = iterator.call(context, value, index, obj);
       behavior(result, key, value);
@@ -499,6 +499,25 @@
     return results;
   };
 
+  // The inverse operation to `_.zip`. If given an array of pairs it
+  // returns an array of the paired elements split into two left and
+  // right element arrays, if given an array of triples it returns a
+  // three element array and so on. For example, `_.unzip` given
+  // `[['a',1],['b',2],['c',3]]` returns the array
+  // [['a','b','c'],[1,2,3]].
+  _.unzip = function(tuples) {
+      var results = [];
+      _.each(tuples, function (tuple, tupleIndex) {
+          _.each(tuple, function (value, itemIndex) {
+              if (results.length <= itemIndex) {
+                  results[itemIndex] = [];
+              }
+              results[itemIndex][tupleIndex] = value;
+          });
+      });
+      return results;
+  };
+
   // Converts lists into objects. Pass either a single array of `[key, value]`
   // pairs, or two parallel arrays of the same length -- one of keys, and one of
   // the corresponding values.
@@ -574,14 +593,25 @@
   // 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). Delegates to **ECMAScript 5**'s native `Function.bind` if
   // available.
   _.bind = function(func, context) {
+    var args, bound;
     if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
-    var args = slice.call(arguments, 2);
-    return function() {
-      return func.apply(context, 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;
+      ctor.prototype = null;
+      var result = func.apply(self, args.concat(slice.call(arguments)));
+      if (Object(result) === result) return result;
+      return self;
     };
   };
 
@@ -598,7 +628,7 @@
   // 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);
+    if (funcs.length === 0) throw new Error("bindAll must be passed function names");
     each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); });
     return obj;
   };
@@ -628,7 +658,7 @@
 
   // Returns a function, that, when invoked, will only be triggered at most once
   // during a given window of time.
-  _.throttle = function(func, wait) {
+  _.throttle = function(func, wait, immediate) {
     var context, args, timeout, result;
     var previous = 0;
     var later = function() {
@@ -638,6 +668,7 @@
     };
     return function() {
       var now = new Date;
+      if (!previous && immediate === false) previous = now;
       var remaining = wait - (now - previous);
       context = this;
       args = arguments;
@@ -728,7 +759,7 @@
   _.keys = nativeKeys || function(obj) {
     if (obj !== Object(obj)) throw new TypeError('Invalid object');
     var keys = [];
-    for (var key in obj) if (_.has(obj, key)) keys[keys.length] = key;
+    for (var key in obj) if (_.has(obj, key)) keys.push(key);
     return keys;
   };
 
@@ -800,7 +831,7 @@
     each(slice.call(arguments, 1), function(source) {
       if (source) {
         for (var prop in source) {
-          if (obj[prop] == null) obj[prop] = source[prop];
+          if (obj[prop] === void 0) obj[prop] = source[prop];
         }
       }
     });
@@ -1055,10 +1086,10 @@
     };
   });
 
-  // If the value of the named property is a function then invoke it;
-  // otherwise, return it.
+  // If the value of the named `property` is a function then invoke it with the
+  // `object` as context; otherwise, return it.
   _.result = function(object, property) {
-    if (object == null) return null;
+    if (object == null) return void 0;
     var value = object[property];
     return _.isFunction(value) ? value.call(object) : value;
   };