Get and Set Nested Objects with JavaScript

By  on  

Back when JavaScript frameworks like MooTools and jQuery ruled the land we all wrote tutorials which were framed more toward the given framework instead of vanilla JavaScript.  Sad but true.  These days I avoid framework-oriented posts since Node.js has taken over the world and JavaScript toolkits come and go.

One very useful post I wrote and still love is Create and Retrieve Nested Objects with MooTools.  In that post I showed you how you can easily get and set nested objects, since doing existence checks down the object chain in a manual way is ... ugly.  Let's tear this functionality out of its MooTools orientation so you can take it with you wherever you go!

The JavaScript

We'll use a simple immediately-executing function to wrap the underlying "worker" function and return an object with properties for getting, setting, and checking existence:

var Objectifier = (function() {

	// Utility method to get and set objects that may or may not exist
	var objectifier = function(splits, create, context) {
		var result = context || window;
		for(var i = 0, s; result && (s = splits[i]); i++) {
			result = (s in result ? result[s] : (create ? result[s] = {} : undefined));
		}
		return result;
	};

	return {
		// Creates an object if it doesn't already exist
		set: function(name, value, context) {
			var splits = name.split('.'), s = splits.pop(), result = objectifier(splits, true, context);
			return result && s ? (result[s] = value) : undefined;
		},
		get: function(name, create, context) {
			return objectifier(name.split('.'), create, context);
		},
		exists: function(name, context) {
			return this.get(name, false, context) !== undefined;
		}
	};

})();

So how would you use this set of functions?  Here are some sample usage examples:

// Creates my.namespace.MyClass
Objectifier.set('my.namespace.MyClass', {
	name: 'David'
});
// my.namespace.MyClass.name = 'David'

// Creates some.existing.objecto.my.namespace.MyClass
Objectifier.set('my.namespace.MyClass', {
	name: 'David'
}, some.existing.objecto); // Has to be an existing object

// Get an object
Objectifier.get('my.namespace.MyClassToo');

// Try to find an object, create it if it doesn't exist
Objectifier.get('my.namespace.MyClassThree', true);

// Check for existence
Objectifier.exists('my.namespace.MyClassToo'); // returns TRUE or FALSE

Notice I didn't extend the Object prototype; you could but we've moved on from that practice.

I use these functions on just about every project I work on.  I find them very useful when dealing with APIs, as you can never assume an object chain exists.  I wish I had included this code within my 7 Essential JavaScript Functions post!

Recent Features

  • By
    Responsive Images: The Ultimate Guide

    Chances are that any Web designers using our Ghostlab browser testing app, which allows seamless testing across all devices simultaneously, will have worked with responsive design in some shape or form. And as today's websites and devices become ever more varied, a plethora of responsive images...

  • By
    5 Awesome New Mozilla Technologies You’ve Never Heard Of

    My trip to Mozilla Summit 2013 was incredible.  I've spent so much time focusing on my project that I had lost sight of all of the great work Mozillians were putting out.  MozSummit provided the perfect reminder of how brilliant my colleagues are and how much...

Incredible Demos

  • By
    Page Visibility API

    One event that's always been lacking within the document is a signal for when the user is looking at a given tab, or another tab. When does the user switch off our site to look at something else? When do they come back?

  • By
    Create Custom Events in MooTools 1.2

    Javascript has a number of native events like "mouseover," "mouseout", "click", and so on. What if you want to create your own events though? Creating events using MooTools is as easy as it gets. The MooTools JavaScript What's great about creating custom events in MooTools is...

Discussion

  1. Rick

    I’ve recently published a PHP Class that does much the same thing but in PHP (with a few extra magic functions) and designed for nested arrays and objects…

    Nest

    $nest = new Nest\Nest();
    $nest->foo__bar = "baz";
    var_dump($nest->doesnt__exist); // null
    var_dump($nest->doesnt__exist("my default")); // "my default"
    
  2. voon ming hann

    lodash has this, it’s _.set(obj, 'a.b.c', 'new value')

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!