Angular Component inheritance without a template in base class

There are several ways of achieving this depending on your use case. For simplicity, you can just create a base component class with a constructor and provide the dependencies from the inheriting or subclass via the super call e.g

export class BaseComponent {
    constructor(modal: ModalService) {
    }
    
    /*
        Implement code and logic common to inheriting components
     */
}

You can now extend this class from your component by injecting the modal service into the child class on passing onto the base class

import {Component, OnInit} from '@angular/core';
import {BaseComponent} from './base.component';
@Component({
    selector: 'app-child',
    templateUrl: './child.component.html',
    styleUrls: ['./child.component.scss'],
})
export class ChildComponent extends BaseComponent implements OnInit {
    constructor(modal: ModalService) {
        super(modal)
    }
}

You can annotate your base component with the @Component angular decorator with an empty template to make your base component life cycle aware

No longer required. Now you can inherit from the base class and never have to supply the service.

import { Component, inject, OnInit } from '@angular/core';
import { MyServiceService } from '../my-service.service';

@Component({
  selector: 'app-my-base-component',
  templateUrl: './my-base-component.component.html',
  styleUrls: ['./my-base-component.component.css']
})
export class MyBaseComponentComponent implements OnInit {
  private service:MyServiceService;
  constructor() {
    this.service = inject(MyServiceService);
  }
  get alive(){
    return this.service.alive;
  }

  ngOnInit() {
  }

}

import { Component, OnInit } from '@angular/core';
import { MyBaseComponentComponent } from '../my-base-component/my-base-component.component';

@Component({
  selector: 'app-my-template',
  templateUrl: './my-template.component.html',
  styleUrls: ['./my-template.component.css']
})
export class MyTemplateComponent extends MyBaseComponentComponent {

  constructor() {
    super();
   }

}