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Why Use AngularJS?

Tuesday, February 26, 2013

AngularJSSince I started a series of posts on AngularJS, I've had a few people ask me why I like the framework.

One year ago I wrote a post with the title "Plain Old JavaScript". This post originated after working with various frameworks and deciding that two-way data binding was not a feature I was willing to achieve by sacrificing JavaScript objects on the Altar Of Observability.

Specifically, the func-ifying of object properties to raise change notifications corrupts my models with infrastructure. The functions make the code harder to change, harder to work on as a team, and harder to debug. These are my personal feelings based on my own observations, and I'm not saying the approach is wrong or doesn't work.

You can like caramel, but I prefer chocolate.

We can both eat ice cream with a dessert topping.


One of the reasons I kept coming back to Angular was because it offers two-way data binding without funcing up the model. At first I couldn't believe the change detection could possibly work, but it does work well by using some smarts. There are watchers, listeners, and a snapshot strategy that will look for changes after your code executes and manipulates the model. The change detection feature includes my favorite comment of the entire Angular code base (in the $digest method):

// Insanity Warning: scope depth-first traversal
// yes, this code is a bit crazy, but it works and we have tests to prove it!

So, it does work, and there are tests to prove it.


Angular is broken down into components like controllers, views, models, and services. These names are familiar to anyone who has worked on projects using separated presentation patterns. There are also directives, filters, modules, and other abstractions that seem to achieve the right balance of complexity versus separation of concerns.


Model View Controller and Dependency Injection are the two patterns that jump out at the start, but there are other comfortable, familiar patterns in Angular, including it's approach to view composition and dependency management. 


Angular help you write test friendly code. Even the tutorial demonstrates unit tests and end-to-end tests using Jasmine's BDD syntax.

What's Wrong with Angular?

Not every framework is perfect, and you'll find scenarios where Angular is not a good fit. There are certainly scenarios when change detection will be milliseconds slower than observing changes. It's not obvious how to track animations or respond to focus events. Form validation is subpar. Angular is not minimalistic and comes with strong opinions. Writing lower level components, like custom directives, requires some focused effort. You also need some understanding of prototypal inheritance to avoid getting into trouble in more advanced scenarios.

Parting Words

I like Angular because I have fun writing code on top of the framework, and the framework doesn't get in the way. Models are just models, and views have sexy {{data.binding}} expressions. I do have an affinity for { and }.

I also believe AngularJS is the framework in the best position to take advantage of future improvements in the JavaScript language and the DOM APIs.

That's why I like AngularJS, but frameworks are a personal choice.