app.component.ts

import { Component, InjectionToken, Inject } from '@angular/core';

export const TOKEN = new InjectionToken<string>('MyToken');

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
  providers: [{ provide: TOKEN, useValue: 'my injected object' }]
})
export class AppComponent {
  constructor(@Inject(TOKEN) public myInjectObject: string) {
    console.log(myInjectObject);
  }
}