What is router outlet in Angular?

In Angular, a router-outlet is a directive that acts as a placeholder for the components to be displayed when a user navigates to a particular route. It is used in the HTML template to define where the content of a component associated with a specific route should be rendered.

For example:

<router-outlet></router-outlet>

In this code, the router-outlet directive acts as a placeholder for the component associated with the active route. When the user navigates to a particular route, the component associated with that route is dynamically loaded and its template is rendered within the router-outlet.

You can also use multiple router-outlet directives to render components in different parts of the template:

<header>Header</header>
<nav>
  <a routerLink="/home">Home</a>
  <a routerLink="/about">About</a>
</nav>
<main>
  <router-outlet></router-outlet>
</main>
<footer>Footer</footer>

In this code, the router-outlet directive is used to render the component associated with the active route within the main section of the template. The header and footer sections are outside of the router-outlet, so they remain unchanged no matter which route the user navigates to.

In summary, the router-outlet directive is used in Angular to define where the content of a component associated with a specific route should be rendered. It acts as a placeholder for the components to be displayed when a user navigates to a particular route.