Book Image

Building Large-Scale Web Applications with Angular

By : Chandermani Arora, Kevin Hennessy, Christoffer Noring, Doguhan Uluca
Book Image

Building Large-Scale Web Applications with Angular

By: Chandermani Arora, Kevin Hennessy, Christoffer Noring, Doguhan Uluca

Overview of this book

<p>If you have been burnt by unreliable JavaScript frameworks before, you will be amazed by the maturity of the Angular platform. Angular enables you to build fast, efficient, and real-world web apps. In this Learning Path, you'll learn Angular and to deliver high-quality and production-grade Angular apps from design to deployment.</p> <p>You will begin by creating a simple fitness app, using the building blocks of Angular, and make your final app, Personal Trainer, by morphing the workout app into a full-fledged personal workout builder and runner with an advanced directive building - the most fundamental and powerful feature of Angular.</p> <p>You will learn the different ways of architecting Angular applications using RxJS, and some of the patterns that are involved in it. Later you’ll be introduced to the router-first architecture, a seven-step approach to designing and developing mid-to-large line-of-business apps, along with popular recipes. By the end of this book, you will be familiar with the scope of web development using Angular, Swagger, and Docker, learning patterns and practices to be successful as an individual developer on the web or as a team in the Enterprise.</p> <p>This Learning Path includes content from the following Packt products:</p> <p><span style="background-color: transparent;">•Angular 6 by Example by Chandermani Arora, Kevin Hennessy&nbsp;</span><br /><span style="background-color: transparent;">•Architecting Angular Applications with Redux, RxJS, and NgRx by Christoffer Noring</span><br /><span style="background-color: transparent;">•Angular 6 for Enterprise-Ready Web Applications by Doguhan Uluca</span></p>
Table of Contents (23 chapters)
Title Page
Copyright
Contributors
About Packt
Preface
Index

Directive injection


Go back a few pages and look at the BusyIndicatorDirective implementation that uses the renderer, specifically the constructor:

constructor(private model: NgModel ...) { } 

Angular automatically locates the NgModel directive created for the directive element and injects it into BusyIndicatorDirective. This is possible because both directives are declared on the same host element.

The good news is that we can influence this behavior. Directives created on a parent HTML tree or child tree can also be injected. The next few sections talk about how to inject directives across the component tree, a very handy feature that allows cross-directive communication for directives that have a common lineage (in a view).

We will use StackBlitz (https://stackblitz.com/edit/angular-pzljm3) to demonstrate these concepts. SlackBlitz is an online IDE to run Angular applications!

To start with, look at the file app.component.ts. It has three directives: Relation, Acquaintance, and Consumer and...