What Is AngularJS?

AngularJS is a discontinued JavaScript framework that helps developers build single-page applications and websites. The framework enforces the model-view-controller (MVC) structure and supports unit testing.

AngularJS was created by a team of Google developers including Miško Hevery. Their main goal was to build a framework that makes it easier to write web apps. As of January 1, 2022, Google no longer updates AngularJS and recommends upgrading to Angular (v2+), though continuing to use AngularJS remains an available option.

How Does AngularJS Work?

AngularJS framework incorporates the model-view-controller (MVC) architecture. MVC is a common web development pattern present in almost all web applications.

The MVC architecture works as follows:

• Models (M) represent the data. For example, in a shopping cart app, a model could represent products. Each product could have an ID, name, price and inventory stored in a database.
• View (V) is the software’s presentation layer. When you visit a web page, you are essentially interacting with the V in that page’s MVC.
• Controller (C) is the layer for business logic. In the view, the software’s end users trigger functions stored in the controller. The controller handles updating the model behind the scenes.

Here’s an example of MVC in action: An e-commerce website has input forms and buttons for adding or deleting items. When you click a button in the view, the input goes to the controller functions. The controller then updates the model as required. The model then sends the updated data back to the view.

The AngularJS framework enforces the MVC pattern by design. Building websites with an MVC pattern provides clear distinction to different parts of the app, which makes development easier and managing the apps more feasible.

Key Features of AngularJS

Some of AngularJS’s notable features include:

MVC

As stated earlier, AngularJS works by using the popular MVC architecture to build web apps. In MVC, the logic lives in three parts: model, view and controller. This makes the AngularJS web apps more manageable and robust.

Data Model Binding

To bind data to HTML components, you don’t need to write tricky and verbose code. Instead, AngularJS allows you to do it easily with simple JavaScript snippets and their respective directives in the HTML objects.

Less Code

To perform document object model (DOM) manipulation in the traditional way, you need a lot of JavaScript code. This is not the case in AngularJS. With Angular, you can write far less code to achieve the same (or more).

Unit Testing

Every developer knows the importance of unit testing. To carry out unit tests in AngularJS, you can use the Karma framework. Google developed Karma specifically for AngularJS to build reliable tests in a breeze.

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Advantages of AngularJS 

Last but not least, let’s go through some of the key advantages of AngularJS.

AngularJS Is Open Source

AngularJS was an open-source framework (as is its successor, Angular). Open-source frameworks receive frequent updates that address bugs and issues quickly, which keep the frameworks relevant and reliable. Obviously, because AngularJS is no longer updated, this is no longer the case.

AngularJS Has a 2-Way Binding Feature

The two-way binding feature keeps your data layer and presentation in sync. Without this feature, you’d need to write extra JavaScript code to do it. In AngularJS, this happens automatically. All you need to do is communicate which control belongs to which part of your model.

AngularJS Manages Routing

AngularJS takes care of the routing, that is, moving between the views. This is a key feature in single-page apps with different pages. The routing feature lets you stay on the same page while moving the functionality around. In practice this means the URL changes while the page remains the same.

AngularJS Allows for Unit Testing

The Karma unit testing feature makes it easy to perform unit and integration tests.

AngularJS Gives Your HTML Components Superpowers 

AngularJS gives directives to HTML components, which provides the HTML components useful behavior without requiring the developer to write code.