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
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Querying child components with the parent component


The @ViewChildren component will provide a reference to all of the children components of a given type as a QueryList, which contains an array of child instances.

Consider the following example:

[app.component.ts]
import { Component, ViewChildren, QueryList } from '@angular/core';

@Component({
  selector: 'child-component',
  template: `
    <h2>Content Header</h2>
    <p *ngIf="flag">Toggleable Content</p>
  `
})
export class ChildComponent {
  private flag: boolean = false;

  toggle(){
    this.flag = !this.flag;
  }
}

@Component({
  selector: 'app-root',
  template: ` 
    <h1>Component Interactions</h1>
    <button (click)="toggle()">Toggle Child</button>
    <child-component></child-component>
    <child-component></child-component>
    <child-component></child-component>
  `
})
export class AppComponent {
  @ViewChildren(ChildComponent)
  private...