Merge pull request mootools#1064 from tmallen/master

Array.pluck

Docs/Types/Array.Extras.md

@@ -187,6 +187,32 @@ Apply a function simultaneously against two values of the array (from right-to-l
 ### See also:
 - [MDC Array.reduceRight][]
 
+Array Method: pluck {#Array.pluck}
+----------------------------------
+
+Returns an array with the named property from each of the array's elements.
+
+### Syntax
+
+	var arr = myArray.pluck(prop)
+
+### Arguments
+1. prop - The named property to access on each element.
+
+### Returns
+
+* (*array*) A new array containing the property value for each element.
+
+### Example
+
+	var foo = [{ a: 1 }, { a: 2 }];
+	var bar = foo.pluck('a'); // bar is [1, 2]
+	var foo2 = [{ a: 1 }, { b: 2 }];
+	var bar2 foo2.pluck('a'); // bar2 is [1, undefined]
+
+### Notes
+
+	Undefined properties are not filtered from the returned array, as shown in the second example.
 
 [Array]: /core/Types/Array
 [MDC Array.reduce]: https://developer.mozilla.org/En/Core_JavaScript_1.5_Reference/Global_Objects/Array/Reduce

Source/Types/Array.Extras.js

@@ -72,6 +72,12 @@ Array.implement({
 			if (i in this) value = value === nil ? this[i] : fn.call(null, value, this[i], i, this);
 		}
 		return value;
+	},
+
+	pluck: function(prop){
+		return this.map(function(item){
+			return item[prop];
+		});
 	}
 
 });

Tests/Specs/1.3/Types/Array.Extras.js

@@ -117,3 +117,15 @@ describe('Array.reduceRight', function(){
 
 });
 
+describe('Array.pluck', function(){
+
+	it('should return the specified property from each element', function(){
+		expect([{ a: 1 }, { a: 2 }].pluck('a')).toEqual([1, 2]);
+	});
+
+	it('should return undefined properties', function(){
+		expect([{ a: 1 }, { b: 2 }].pluck('a')).toEqual([1, undefined]);
+	});
+
+});
+