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

Understanding structural directives


While we will often be using structural directives, such as NgIf and NgFor, there is seldom a need to creating a structural directive. Think carefully. If we need a new view, we create a component. If we need to extend an existing element/component, we use a directive. Whereas the most common use of structural directives is to clone a piece of a view (also called a template view) and then, based on some conditions:

  • Either inject/destroy these templates (NgIf and NgSwitch)
  • Or duplicate these templates (NgFor)

Any behavior implemented using structure directives will inadvertently fall into either of these two categories.

Given this fact, instead of building our own structural directive, let's look at the source code of the NgIf implementation.

The following is an excerpt from the NgIf directive that is of interest to us. We have ignored the ngIfElse parts from the excerpt intentionally:

@Directive({selector: '[ngIf]'})
export class NgIf {
 constructor(private...