The Angular Router NgModule provides a service that lets you define a navigation path among the different application states and view hierarchies in your app. It is modeled on the familiar browser navigation conventions:
- Enter a URL in the address bar and the browser navigates to a corresponding page.
- Click links on the page and the browser navigates to a new page.
- Click the browser’s back and forward buttons and the browser navigates backward and forward through the history of pages you’ve seen.
The router maps URL-like paths to views instead of pages. When a user performs an action, such as clicking a link, that would load a new page in the browser, the router intercepts the browser’s behavior, and shows or hides view hierarchies.
If the router determines that the current application state requires particular functionality, and the module that defines it has not been loaded, the router can lazy-load the module on demand.
The router interprets a link URL according to your app’s view navigation rules and data state. You can navigate to new views when the user clicks a button, selects from a drop box, or in response to some other stimulus from any source. The Router logs activity in the browser’s history journal, so the back and forward buttons work as well.
To define navigation rules, you associate navigation paths with your components. A path uses a URL-like syntax that integrates your program data, in much the same way that template syntax integrates your views with your program data. You can then apply program logic to choose which views to show or to hide, in response to user input and your own access rules.
Most routing applications should add a <base> element to the index.html as the first child in the <head> tag to tell the router how to compose navigation URLs. If the app folder is the application root, as it is for the sample application, set the href value exactly as shown here.