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When building AngularJS apps, it can be challenging to access data and services hidden deep in our application through the Javascript console in Chrome, Firefox, and IE. Here are some simple tricks we can use to inspect and control a running Angular app through the browser Javascript console, making it easy to test, modify, and even program our Angular app in real-time:

1: Access Scopes

We can access any scope (even isolated ones!) on the page with a simple JS one-liner:

> angular.element(targetNode).scope()
-> ChildScope {$id: "005", this: ChildScope, $$listeners: Object, $$listenerCount: Object, $parent: Scope…}

Or for isolated scopes:

> angular.element(targetNode).isolateScope()
-> Scope {$id: "009", $$childTail: ChildScope, $$childHead: ChildScope, $$prevSibling: ChildScope, $$nextSibling: Scope…}

Where targetNode is a reference to an HTML Node. You can grab one easily using document.querySelector().

2: Inspect the Scope Tree

Sometimes we need to see what the scopes look like on the page to effectively debug our app. The AngularJS Batarang is a Chrome extension that shows the live scope hierarchy and has some other really helpful features.

Batarang Scopes

3: Grab any Services

We can grab a reference to any service using the injector function of element where ngApp was defined, or indirectly though any element with the ng-scope class:

> angular.element(document.querySelector('html')).injector().get('MyService')
-> Object {undo: function, redo: function, _pushAction: function, newDocument: function, init: function…}
// Or slightly more generic
> angular.element(document.querySelector('.ng-scope')).injector().get('MyService')

We can then call methods on that service just like we could if we injected it.

4: Access controller for directive

Some directives define a controller with certain additional (often shared) functionality. To access the instance of a controller for a given directive from the console, just use the controller() function:

> angular.element('my-pages').controller()
-> Constructor {}

This last one is more advanced and not used as frequently.

5: Chrome Console Features

Chrome has a ton of nice shortcuts for debugging browser applications from the console. Here are some of the best ones for Angular development:

  • $0$4: Access the last 5 DOM elements selected in the inspector window. This is convenient for grabbing scopes for selected elements: angular.element($0).scope()

  • $(selector) and $$(selector): A quick replacement for querySelector() and querySelectorAll, respectively.

Thanks to @zgohr for this tip!

Conclusion

With a few simple tricks we can access the data for any scope on the page, inspect the scope hierarchy, inject services, and control directives.

So the next time you want to make small tweaks, check your work, or control an AngularJS app from the console, I hope you’ll remember these commands and find them as useful as I do!

  • Estevan Saucedo

    batarang is known to not work with ionic. or maybe it was fixed and im doing something wrong?

    • Andy Barr

      I have never managed to get any useful info from Batarang with Ionic either.

      • http://gonehybrid.com/ Ashteya

        I use ng-inspect instead of Batarang.

        • OlegM

          Yep using ng-inspector as well. Bataran has a few versions and they’re all over the place in terms of consistency. Half the time Batarang says there are 0 scopes on the page…I gave up and moved on to ng-inspect