Added _.propertyOf method and tests

test/utility.js

@@ -40,6 +40,24 @@
     equal(_.property('name')(null), undefined, 'should return undefined for null values');
     equal(_.property('name')(undefined), undefined, 'should return undefined for undefined values');
   });
+
+  test('propertyOf', function() {
+    var stoogeRanks = _.propertyOf({curly: 2, moe: 1, larry: 3});
+    equal(stoogeRanks('curly'), 2, 'should return the property with the given name');
+    equal(stoogeRanks(null), undefined, 'should return undefined for null values');
+    equal(stoogeRanks(undefined), undefined, 'should return undefined for undefined values');
+
+    function MoreStooges() { this.shemp = 87; }
+    MoreStooges.prototype = {curly: 2, moe: 1, larry: 3};
+    var moreStoogeRanks = _.propertyOf(new MoreStooges());
+    equal(moreStoogeRanks('curly'), 2, 'should return properties from further up the prototype chain');
+
+    var nullPropertyOf = _.propertyOf(null);
+    equal(nullPropertyOf('curly'), undefined, 'should return undefined when obj is null');
+
+    var undefPropertyOf = _.propertyOf(undefined);
+    equal(undefPropertyOf('curly'), undefined, 'should return undefined when obj is undefined');
+  });
 
   test('random', function() {
     var array = _.range(1000);

underscore.js

@@ -1215,6 +1215,13 @@
       return obj == null ? void 0 : obj[key];
     };
   };
+
+  // Generates a function for a given object that returns a given property (including those of ancestors) 
+  _.propertyOf = function(obj) {
+    return obj == null ? _.noop : function(key) {
+      return obj[key];
+    };
+  };
 
   // Returns a predicate for checking whether an object has a given set of `key:value` pairs.
   _.matches = function(attrs) {