Returning only certain properties from an array of objects in Javascript [duplicate]

This is easily done with the Array.prototype.map() function:

var keyArray = objArray.map(function(item) { return item["key"]; });

If you are going to do this often, you could write a function that abstracts away the map:

function pluck(array, key) {  return array.map(function(item) { return item[key]; });}

In fact, the Underscore library has a built-in function called pluck that does exactly that.

var object = function(key,text) {    this.key = key;    this.text = text;}var objArray = [];objArray[0] = new object('key1','blank');objArray[1] = new object('key2','exampletext');objArray[2] = new object('key3','moretext');var keys = objArray.map(function(o,i) {  return o.key;});console.log(keys); // ["key1", "key2", "key3"]

JS Bin Example

http://jsbin.com/vamey/1/edit

Note that older browsers may not support map but you can easily do this with a for loop:

var keys = [];for (var i = 0; i < objArray.length; i++) {  keys.push(objArray[i].key);}

JS Bin Example

http://jsbin.com/redis/1/edit

You would want to do something like this:

objArray.map(function (obj) { return obj.key; });

Here is a JSFiddle to demo: http://jsfiddle.net/Q7Cb3/

If you need older browser support, you can use your own method:

JSFiddle demo: http://jsfiddle.net/Q7Cb3/1/

function map (arr, func) {    var i = arr.length;    arr = arr.slice();    while (i--) arr[i] = func(arr[i]);    return arr;}