Book Image

Angular 2 Components

By : Thierry Templier Thierry
Book Image

Angular 2 Components

By: Thierry Templier Thierry

Overview of this book

This book is a concise guide to Angular 2 Components and is based on the stable version of Angular 2. You will start with learning about the Angular 2 Components architecture and how components differ from Angular directives in Angular 1. You will then move on to quickly set up an Angular 2 development environment and grasp the basics of TypeScript. With this strong foundation in place, you will start building components. The book will teach you, with an example, how to define component behavior, create component templates, and use the controller of your component. You will also learn how to make your components communicate with each other. Once you have built a component, you will learn how to extend it by integrating third-party components with it. By the end of the book, you will be confident with building and using components for your applications.
Table of Contents (16 chapters)
Angular 2 Components
About the Authors
About the Reviewers

Emitting custom events

When the child component needs to communicate with its parent component, it can emit an event. This technique keeps the child component de-coupled from its parent (de-coupled: doesn't need to know its parents).

In Angular, we need to use a class named EventEmitter if we want to emit events.

You need to instantiate the EventEmitter class, assign it to a class property, and call the emit method.

In the following example, the child component will emit a custom event named TitleClicked when the user clicks on the title:

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

  selector: 'child-component',
  template: `<h2 (click)="titleClicked.emit()">{{ title }}</h2>`
export class ChildComponent {
  @Input() private title: string;
  @Output() private titleClicked = new EventEmitter<any>();

  selector: 'app-root',
  template: ` 
    <h1>Component Interactions</h1>