AngularJS, what is it?

AngularJS, Simply Put

AngularJS

AngularJS is a JavaScript framework. It provides an Application Programming Interface (API) that allows you to build web applications using JavaScript, HTML, & CSS. The API that Angular provides is a well thought out and robust set of solutions that provide you the ability to create powerful web applications more simply & quickly.

AngularJS lets you extend HTML vocabulary for your application. The resulting environment is extraordinarily expressive, readable, and quick to develop. – angularjs.org

Thinking Differently

For me, and I’m imagining many others, Angular required a paradigm shift in the way I thought about application development. Angular doesn’t just allow you to manipulate the DOM. What angular does is allow you as the developer to extend the existing features of HTML and add on to the capabilities of the browser in a very slick way. Angular’s angle (ha!) is to control the view by inspecting the DOM for an injection point where you can hen create the features of your application. These injections can be objects that act as the logical control center for an existing tag like an <h1> or adding on attributes to that same tag. Angular also allows you to create completely new tags that can be used in you application. The result then become the components, views and logic of you’re application.

The point being is that now you have control over the features and functionality of the browser for your application. Understanding how your new features features are added to the browser, and how you can best structure your application to allow for simplified and maintainable development is the first step. The way I tend to think of it is that Angular is responsible for telling the browser what to do, you just need to provide the logic and data to allow it to do so. That is a very important concept to grasp with Angular – the data is what drives the application. You don’t, and shouldn’t, manipulate the DOM directly. You change the data, then it is up to angular to render the view correctly based on that data.

For example, instead of using jQuery (or angular’s jQLite) to manipulate the DOM to show some text or change a class, we change the data model. This change is evaluated and angular then updates and renders the view appropriately based on that changed data. You can see this in the sample below:

The displayed H1 value changes when we type into the text input. This is Angular being notified that the model has updated and that the view needs to re-render the updated data. There is nothing we need to do programmatically to set the “innerHTML” of a specific div with the new data. Also notice that there is no custom JavaScript in the jsFiddle above. We only have to include the library & specify the model & bindings.

For me, it took some time to get it. But, once I did, I loved it!

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