Event Emitter via two different components (no parent/child)

Angular event emitter connection

In this scenario we have no connection between two components.
If you have parent/child scenario you can use @Input, @Output system of angular (explained in other places).

The ingredients for our recipe are:

  • 1 EventEmitter
  • 1 service
  • 2 components

We can start adding a service with, inside it, an event emitter.

service 💾

// ~/sign-in.service.ts
import { EventEmitter, Injectable } from '@angular/core';

export class SignInService {
  public username = new EventEmitter<string>();

  constructor() { }


Now we create our example components to use it.

Header component 💾

// ~/header.component.ts
import { Component, OnInit } from '@angular/core';
import { SignInService } from '../sign-in.service';

  selector: 'app-header',
  template: `<header>
              Hello<span *ngIf="username">{{' ' + username}}</span>!
  styleUrls: ['./header.component.css']
export class HeaderComponent implements OnInit {
  public username;

  constructor(private _signInService: SignInService) {
      (data: string) => {
          this.username = data;

  ngOnInit() {

  ngOnDestroy() {

With its style:

/* ~/header.component.css */
header {
  box-sizing: border-box;
  height: 60px;
  width: 100%;
  background-color: #1389fd;
  color: white;
  position: absolute;
  top: 0;
  right: 0;
  left: 0;
  line-height: 40px;
  padding: 10px 10%;
  font-family: Lato;
  font-size: 24px;
  text-align: right;

component 💾

// ~/sign-in.component.ts
import { Component, OnInit } from '@angular/core';
import { NgForm } from '@angular/forms';
import { SignInService } from '../sign-in.service';

  selector: 'app-sign-in',
  templateUrl: './sign-in.component.html',
  styleUrls: ['./sign-in.component.css']
export class SignInComponent implements OnInit {
  public username: string;
  constructor(private _signInService: SignInService) {}
  public handleSubmit(f: NgForm): void {

  ngOnInit() {}

With its template and style:

<!-- ~/sign-in.component.html -->
<form #f="ngForm" (ngSubmit)="handleSubmit(f)">
  <!-- username field -->
  <label for="username">Username: </label>
  <input #usr="ngModel" id="username" name="username"
        [(ngModel)]="username" class="form-control" required  minlength="3">
  <!-- submit button -->
  <button type="submit" class="btn btn-primary">SEND</button>
/* ~/sign-in.component.css */
form {
  box-sizing: border-box;
  background-color: white;
  color: black;
  padding: 10px 10%;
  font-family: Lato;
  font-size: 18px;
  text-align: center;

Now, when we click on submit Send button we can see our username inserted in the header component.

Here you can see a working example:

Try it at home!

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  1. Like!! I blog frequently and I really thank you for your content. The article has truly peaked my interest.

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