In Angular, RouterLink
is a directive for navigating to a different route declaratively. Router.navigate
and Router.navigateByURL
are two methods available to the Router
class to navigate imperatively in your component classes.
Let’s explore how to use RouterLink
, Router.navigate
, and Router.navigateByURL
.
A typical link in HTML looks like this:
<a href="/example">
Example HTML link.
</a>
This example link will direct the user to the /example
page.
However, a single page application (SPA) does not have different pages to link to. Instead, it has different views to display to the user. To allow a user to navigate and change the view, you will want to use the RouterLink
directive instead of href
:
<a routerLink="/users/sammy">
Link that uses a string.
</a>
This RouterLink
example will direct the user to the component at /users/sammy
.
The different URL segments can also be passed in an array like this:
<a [routerLink]="['/', 'users', 'sammy']">
Link that uses an array.
</a>
These two examples are formatted differently but will be directed to the same component at /users/sammy
.
You can use '../
to go up to higher levels in the navigation using something like this:
<a [routerLink]="['../', 'posts', 'sammy']">
Link that goes up a level.
</a>
In that example, if the user is at /users/sammy
, the navigation will change to /posts/sammy
.
It is possible to prepend the first URL segment with a ./
, ../
, or no leading slash.
You can pass in parameters to the navigation with an object in the list of URL segments:
<a [routerLink]="['/', 'users', {display: 'verbose'}, 'sammy']">
Link with parameter.
</a>
In that example, the Router
will navigate to /users;display=verbose/sammy
.
You can tell the Router
what to place in a named outlet
with something like this:
<a [routerLink]="['/', 'users', { outlets: { side: ['sammy'] } }]">
Link with a side outlet.
</a>
In that example, the sammy
segment will be placed in the outlet
named side
.
It is also possible to tell the Router
what to place in multiple named outlet
s with something like this:
<a [routerLink]="['/', 'users', { outlets: { side: ['sammy'], footer: ['sharks'] } }]">
Link with a side and footer outlets.
</a>
In this example, the sammy
segment will be placed in the outlet
named side
and the sharks
segment will be placed in the outlet
named footer
.
There are two methods available on Angular’s Router
class to navigate imperatively in your component classes: Router.navigate
and Router.navigateByUrl
. Both methods return a promise that resolves to true
if the navigation is successful, null
if there’s no navigation, false
if the navigation fails, or is completely rejected if there’s an error.
To use either method, you’ll first want to make sure that the Router
class is injected into your component class.
First, import Router
into your component class:
import { Component } from '@angular/core';
import { Router } from '@angular/router';
Then, add Router
to the dependencies:
@Component({
// ...
})
export class AppComponent {
constructor(private router: Router) {
// ...
}
// ...
}
Now, you can use Router.navigate
or Router.navigateByUrl
.
You pass in an array of URL segments to Router.navigate
.
Here’s a basic example using the Router.navigate
method:
goPlaces() {
this.router.navigate(['/', 'users']);
}
And here’s an example demonstrating how Router.navigate
is thenable:
goPlaces() {
this.router.navigate(['/', 'users'])
.then(nav => {
console.log(nav); // true if navigation is successful
}, err => {
console.log(err) // when there's an error
});
}
If Router.navigate
is successful in this example, it will display true
. If Router.navigate
is unsuccessful in this example, it will display an error.
Router.navigateByUrl
is similar to Router.navigate
, except that a string is passed in instead of URL segments. The navigation should be absolute and start with a /
.
Here’s a basic example using the Router.navigateByUrl
method:
goPlaces() {
this.router.navigateByUrl('/users;display=verbose/sammy');
}
In this example, Router.navigateByUrl
will navigate to /users;display=verbose/sammy
.
In this article, you learned about navigation in Angular applications. You were introduced to RouterLink
, Router.navigate
, and Router.navigateByURL
.
If you’d like to learn more about Angular, check out our Angular topic page for exercises and programming projects.
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Very helpfull article