Angular 4 call parent method in a child component

import { Output, EventEmitter } from '@angular/core'; 

...

class ChildComponent {
  @Output() someEvent = new EventEmitter<string>();

  callParent(): void {
    this.someEvent.next('somePhone');
  }
}

In ContactInfo's template

<child-component (someEvent)="deletePhone($event)"

This worked for me (example from official docs):

https://angular.io/api/core/EventEmitter#examples

Child:

@Component({
  selector: 'zippy',
  template: `
  <div class="zippy">
    <div (click)="toggle()">Toggle</div>
    <div [hidden]="!visible">
      <ng-content></ng-content>
    </div>
 </div>`})
export class Zippy {
  visible: boolean = true;
  @Output() open: EventEmitter<any> = new EventEmitter();
  @Output() close: EventEmitter<any> = new EventEmitter();

  toggle() {
    this.visible = !this.visible;
    if (this.visible) {
      this.open.emit(null); //emit event here
    } else {
      this.close.emit(null);
    }
  }
}

Parent:

<zippy (open)="onOpen($event)" (close)="onClose($event)"></zippy>

I don't like boilerplate code like @Output(). I found another solution, just pass object with any number of anonymous functions

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

@Component({
  selector: 'app-parent',
  styleUrls: ['./parent.component.css'],
  template: `
  <app-child [parentApi]="getParentApi()"></app-child>
`,
})
export class ParentComponent implements OnInit {

  getParentApi(): ParentComponentApi {
    return {
      callParentMethod: (name) => {
        this.parentMethod(name)
      }
    }
  }

  constructor() { }

  ngOnInit() {
  }

  parentMethod(name: string) {
    console.log(`Hello ${name} from parent`)
  }
  
}

export interface ParentComponentApi {
  callParentMethod: (string) => void
}

And child:

import { Component, OnInit, Input } from '@angular/core';
import { ParentComponentApi } from '../parent/parent.component';

@Component({
  selector: 'app-child',
  template: `<button (click)="callParent()">call parent</button>`,
  styleUrls: ['./child.component.css']
})
export class ChildComponent implements OnInit {

  @Input() parentApi: ParentComponentApi

  constructor() { }

  callParent() {
    this.parentApi.callParentMethod("child")
  }

  ngOnInit() {

  }

}

I think this is pretty safe to do this way, no?

It's simpler than you might think. The key is to pass a parent method to a child @Input property. test it online

Parent component

@Component({
  selector: 'my-app',
  template: `
    <h1>Parent:</h1>
    <p>Parent counting: {{this.count}}</p>

    <child-comp [childInc]="this.inc"></child-comp>
  `
})
export class AppComponent {
  name = "I'm Parent";

  count = 0;

  inc = () => {
    this.count++;
  }
}

Child component

@Component({
  selector: 'child-comp',
  template: `
  <h1>Child:</h1> 
  <button (click)="childInc()">Click me!</button>
  `
})
export class ChildComponent  {
  name = "I'm child"

  @Input() childInc: () => void
}

I've used inc = () => {...} notion in parent, which can remember the right this. If you use the inc(){...} notion, then you need to bind parent this as [childInc]="this.inc.bind(this)".