adding an initial implementation of a 'pick' function. #523

index.html

@@ -214,6 +214,7 @@
       <li>- <a href="#values">values</a></li>
       <li>- <a href="#object-functions">functions</a></li>
       <li>- <a href="#extend">extend</a></li>
+      <li>- <a href="#pick">pick</a></li>
       <li>- <a href="#defaults">defaults</a></li>
       <li>- <a href="#clone">clone</a></li>
       <li>- <a href="#tap">tap</a></li>
@@ -1016,16 +1017,14 @@ _.extend({name : 'moe'}, {age : 50});
 =&gt; {name : 'moe', age : 50}
 </pre>
 
-      <p id="restrict">
+      <p id="pick">
-        <b class="header">restrict</b><code>_.restrict(source, *keys)</code>
+        <b class="header">pick</b><code>_.pick(object, *keys)</code>
         <br />
-        Return a clone of the <b>source</b> with only the properties with the
+        Return a copy of the <b>object</b>, filtered to only have values for
-        property names, or arrays of property names, provided in <b>keys</b>.
+        the whitelisted <b>keys</b> (or array of valid keys).
       </p>
       <pre>
-_.restrict({name : 'moe', age: 50, userid : 'moe1'}, 'name', 'age');
+_.pick({name : 'moe', age: 50, userid : 'moe1'}, 'name', 'age');
-=&gt; {name : 'moe', age : 50}
-_.restrict({name : 'moe', age: 50, userid : 'moe1'}, ['name', 'age']);
 =&gt; {name : 'moe', age : 50}
 </pre>
 

test/objects.js

@@ -41,13 +41,13 @@ $(document).ready(function() {
     equal(_.keys(result).join(''), 'ab', 'extend does not copy undefined values');
   });
 
-  test("objects: restrict", function() {
+  test("objects: pick", function() {
     var result;
-    result = _.restrict({a:1, b:2, c:3}, 'a', 'c');
+    result = _.pick({a:1, b:2, c:3}, 'a', 'c');
     ok(_.isEqual(result, {a:1, c:3}), 'can restrict properties to those named');
-    result = _.restrict({a:1, b:2, c:3}, ['b', 'c']);
+    result = _.pick({a:1, b:2, c:3}, ['b', 'c']);
     ok(_.isEqual(result, {b:2, c:3}), 'can restrict properties to those named in an array');
-    result = _.restrict({a:1, b:2, c:3}, ['a'], 'b');
+    result = _.pick({a:1, b:2, c:3}, ['a'], 'b');
     ok(_.isEqual(result, {a:1, b:2}), 'can restrict properties to those named in mixed args');
   });
 
@@ -178,7 +178,7 @@ $(document).ready(function() {
 
     // Arrays with primitive and object values.
     ok(_.isEqual([1, "Larry", true], [1, "Larry", true]), "Arrays containing identical primitives are equal");
-    ok(_.isEqual([/Moe/g, new Date(2009, 9, 25)], [/Moe/g, new Date(2009, 9, 25)]), "Arrays containing equivalent elements are equal");
+    ok(_.isEqual([(/Moe/g), new Date(2009, 9, 25)], [(/Moe/g), new Date(2009, 9, 25)]), "Arrays containing equivalent elements are equal");
 
     // Multi-dimensional arrays.
     var a = [new Number(47), false, "Larry", /Moe/, new Date(2009, 11, 13), ['running', 'biking', new String('programming')], {a: 47}];
@@ -346,7 +346,7 @@ $(document).ready(function() {
     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']
+      delete this_date_components['_type']; delete that_date_components['_type'];
       return _.isEqual(this_date_components, that_date_components);
     };
 

underscore.js

@@ -648,14 +648,13 @@
     return obj;
   };
 
-  // Restrict a given object to the properties named
+  // Return a copy of the object only containing the whitelisted properties.
-  _.restrict = function(obj) {
+  _.pick = function(obj) {
-    if (obj !== Object(obj)) throw new TypeError('Invalid object');
+    var result = {};
-    var dest = {};
+    each(_.flatten(slice.call(arguments, 1)), function(key) {
-    each(_.flatten(slice.call(arguments, 1)), function(prop) {
+      if (key in obj) result[key] = obj[key];
-      if (prop in obj) dest[prop] = obj[prop];
     });
-    return dest;
+    return result;
   };
 
   // Fill in a given object with default properties.