AngularJS, a popular framework for building single-page applications (SPAs), has always supported routing and history management through the ngRoute module. However, ngRoute has limitations, especially when it comes to building complex SPAs. It doesn’t support nested and parallel views, which are crucial for complex applications. To overcome these limitations, AngularJS introduced a new component router in Angular 1.4 and Angular 2.0.
Understanding the Component Router
The component router is designed to provide routing at the component level. This means that each separate component in your application will have its own route and URL. The component router helps you break down your application into smaller mini applications, allowing you to build smaller working components and then combine them into a giant single page application.
Setting Up the Component Router
To set up the component router, you’ll need to install it using npm. Navigate to your working directory in your command line tool and run npm install angular-new-router. This will download the necessary files required for the component router. Alternatively, you can download the file directly from the AngularJS website.
Once you’ve installed the component router, you can set up your index.html file. Include Angular 1.4 and the JavaScript library for the new router in your file. You’ll also need to include app.js, where you’ll define your main app and controller. On the body tag, define your Angular module and controller.
Next, place the ng-viewport directive where you’d like your route to load HTML content. The ng-viewport directive is provided by the component router and is similar to the ng-view directive in ngRoute.
Configuring Routes
With the component router, you configure your routes within the controller itself. You can define a component and the URL for that component. However, before you can do this, you’ll need to create the component.
A component in AngularJS is a module that exports a class or a set of utilities that perform a similar task. By default, the component router serves from the ./components directory. A component called myWidget, for example, loads the template from ./components/my-widget/my-widget.html and uses a controller named MyWidgetController.
Linking to Views
The component router provides the ng-link directive to link to different views. This is similar to the ng-href directive in ngRoute. The syntax for ng-link is componentName({optional params}). So, if you want to link to your home view, you would write <a ng-link="home()">Home</a>.
Parallel Views
One of the advantages of the component router is that it allows you to have multiple ng-viewport directives on the same page, thereby supporting parallel views. This means you can display multiple views on the same page at the same time.
Conclusion
The component router in AngularJS overcomes the limitations of ngRoute and enables you to build complex single-page applications. It also helps to modularize your app into smaller components and provide routing at the component level. While the component router is still in development, it’s worth exploring and experimenting with, as it will make your transition to Angular 2.0 easier.
