Can you get the component encapsulation host ID?

Question

Is there a way to get the encapsulation host id that is given to a component?

If you have a component that is using ViewEncapsulation.Emulated the eleme

Answer 1

This ID consists of the following parts:

_nghost   -   par    -     2
   |           |           |
 static      APP_ID   _nextCompTypeId

APP_ID is a just token from @angular/core

If you need to avoid randomly generated value to be used as an application id, you can provide a custom value via a DI provider configuring the root Injector using this token

_nextCompTypeId is generated inside framework within private class ViewUtils.

Seems there is no a public method which can return it value. So probably the following will work

export class MyComponent { 
  id: string;
  constructor(@Inject(APP_ID) appId: string, vcRef: ViewContainerRef) {
    this.id = `${appId}-${vcRef.injector['_view'].viewUtils._nextCompTypeId - 1}`;
  }
}

Another way is get it from attributes via elementRef

Update

If you're on Angular 9 then follow this answer How to access components unique encapsulation ID in Angular 9