Using parent component's template in Angular2

Question

I want to inherit parent's template using component's inheritance in Angular.

Intro

I have some basic component (let's call it ParentComponent) and several childs of this component (Child1Component and Child2Component). I want to put default behavior in the ParentComponent and then just setup/extend this behavior in children components. ParentComponent template already contains all the needed things, so I want children components to use this template by default.

---

First variant of implementation (does not work, Error: No template specified for component Child1Component):

@Component({
    selector: 'app-parent',
    templateUrl: './app-parent.component.html',
    styleUrls: ['./app-parent.component.scss']
})
export class ParentComponent {
}

@Component({
    selector: 'app-child1'
})
export class Child1Component extends ParentComponent {
}


@Component({
    selector: 'app-child2'
})
export class Child2Component extends ParentComponent {
}

---

I found that I can set templateUrl and styleUrls of children to parent's template, but it will work only if ViewEncapsulation of children is set to None.

Second variant (it works, but I don't like it):

@Component({
    selector: 'app-parent',
    templateUrl: './app-parent.component.html',
    styleUrls: ['./app-parent.component.scss']
})
export class ParentComponent {
}

@Component({
    selector: 'app-child1',
    templateUrl: '../parent/app-parent.component.html',
    styleUrls: ['../parent/app-parent.component.scss'],
    encapsulation: ViewEncapsulation.None
})
export class Child1Component extends ParentComponent {
}

@Component({
    selector: 'app-child2',
    templateUrl: '../parent/app-parent.component.html',
    styleUrls: ['../parent/app-parent.component.scss'],
    encapsulation: ViewEncapsulation.None
})
export class Child2Component extends ParentComponent {
}

I don't like this solution cause of

1. No view encapsulation in child components;
2. Template and style urls copy-paste for every child component.

---

Can you please suggest me better solution for this task?

Answer 1

Second approach is the only possible way, because there are rules for decorator inheritance, see https://github.com/angular/angular/issues/11606.

@Component decorator can not be partially inherited, it is all or nothing.