What Is RouterLinkActive?
The RouterLinkActive is a directive. To add the active CSS class to the element when the associated RouterLink becomes active (visually look like selected anchors). It is also works for both parent and child elements.
@Directive({
selector: '[routerLinkActive]',
exportAs: 'routerLinkActive'
})
Consider the following example for active a link –
<a routerLink="/user/detail" routerLinkActive="active-link">User Detail</a>
You can also set more than one class and it look like this.
<a routerLink="/user/detail" routerLinkActive="active-class1 active-class2">User detail</a>
<a routerLink="/user/detail" [routerLinkActive]="['active-class1', 'active-class2']">User detail</a>
For
more detail kindly refer the link - https://www.code-sample.com/2018/05/angular-5-6-7-routing-and-navigation.html