Get array of object's keys

Question

I would like to get the keys of a JavaScript object as an array, either in jQuery or pure JavaScript.

Is there a less verbose way than this?

var foo = { 'alpha' : 'puffin', 'beta' : 'beagle' }; var keys = []; for (var key in foo) {     keys.push(key); } 

Answer 1

Use Object.keys:

var foo = {   'alpha': 'puffin',   'beta': 'beagle' };  var keys = Object.keys(foo); console.log(keys) // ['alpha', 'beta']  // (or maybe some other order, keys are unordered).

This is an ES5 feature. This means it works in all modern browsers but will not work in legacy browsers.

The ES5-shim has a implementation of Object.keys you can steal

Answer 2

You can use jQuery's $.map.

var foo = { 'alpha' : 'puffin', 'beta' : 'beagle' }, keys = $.map(foo, function(v, i){   return i; });