Navigation model

Create a navigation menu using navigation model in Router-Lite.

The navigation model can be thought of as view-friendly version of the configured routes. It provides similar information as of the configured routes with some additional data to it. This is typically useful when you want to create navigation menu from the already registered/configured routes in the router, without necessarily duplicating the data. The information takes the following shape.

interface INavigationModel {
  /**
   * Collection of routes.
   */
  readonly routes: readonly {
    readonly id: string;
    readonly path: string[];
    readonly redirectTo: string | null;
    readonly title: string | ((node: RouteNode) => string | null) | null;
    readonly data: Record<string, unknown>;
    readonly isActive: boolean;
  }[];
}

Note that apart from isActive, all other properties of the route object are same as the corresponding configured route.

This section provides example of how to use navigation model while discussing different aspects of it.

Create a navigation menu using a navigation model

The following example shows how to create a navigation menu using the info from the navigation model.

In this example, we are using a custom element named nav-bar. In the custom element we inject an instance of IRouteContext and we grab the navigation model from the routing context.

import { INavigationModel, IRouteContext } from '@aurelia/router-lite';

export class NavBar {
  private readonly navModel: INavigationModel;
  public constructor(@IRouteContext routeCtx: IRouteContext) {
    this.navModel = routeCtx.navigationModel;
  }

  public async binding() {
    await this.navModel.resolve()
  }
}

Then the information from the model is used in the view to create the navigation menu.

<nav style="display: flex; gap: 0.5rem;">
    <template repeat.for="route of navModel.routes">
        <a href.bind="route.path | firstNonEmpty">\${route.title}</a>
    </template>
</nav>

It additionally shows that from the NavBar#binding, INavigationModel#resolve() is awaited. This is recommended, when dealing with async route configuration. This allows all the promises to be resolved and thereafter building the navigation information correctly.

Note that in the example above we aren't dealing with async routing. Therefore, for that example waiting the INavigationModel#resolve() can be avoided.

Using the isActive property

The isActive property is true when this route is currently active (loaded), and otherwise it is false. A typical use-case for this property is to apply or remove the "active" style to the links, depending on if the link is active or not. You can see this in the following example where a new .active class is added and that is bound to the isActive property.

<style>
  .active {
    font-weight: bold;
  }
</style>
<nav>
  <template repeat.for="route of navModel.routes">
    <a href.bind="route.path | firstNonEmpty" active.class="route.isActive">${route.title}</a>
  </template>
</nav>

You can see this in action below.

Excluding routes from the navigation model

By default, all configured routes are added to the navigation model. However, there might be routes which is desired to be excluded from the navigation model; for example: a fallback route for un-configured routes. To this end, a route can be configured with nav: false to instruct the router not to included it in the navigation model.

import { route } from '@aurelia/router-lite';
import { Home } from './home';
import { About } from './about';
import { NotFound } from './not-found';

@route({
  routes: [
    {
      path: ['', 'home'],
      component: Home,
      title: 'Home',
    },
    {
      path: 'about',
      component: About,
      title: 'About',
    },
    {
      path: 'notfound',
      component: NotFound,
      title: 'Not found',
      nav: false,       // <-- exclude from navigation model
    },
  ],
  fallback: 'notfound',
})
export class MyApp {}

You see this in action in the example below.

Disabling navigation model

If you are not creating a menu using the navigation model, you can also deactivate the navigation model by setting false to the useNavigationModel router option. Doing so, will set the IRouteContext#navigationModel to null and skip further processing.

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