Book Image

Learning Angular - Third Edition

By : Aristeidis Bampakos, Pablo Deeleman
Book Image

Learning Angular - Third Edition

By: Aristeidis Bampakos, Pablo Deeleman

Overview of this book

Angular, loved by millions of web developers around the world, continues to be one of the top JavaScript frameworks thanks to its regular updates and new features that enable fast, cross-platform, and secure frontend web development. With Angular, you can achieve high performance using the latest web techniques and extensive integration with web tools and integrated development environments (IDEs). Updated to Angular 10, this third edition of the Learning Angular book covers new features and modern web development practices to address the current frontend web development landscape. If you are new to Angular, this book will give you a comprehensive introduction to help you get you up and running in no time. You'll learn how to develop apps by harnessing the power of the Angular command-line interface (CLI), write unit tests, style your apps by following the Material Design guidelines, and finally deploy them to a hosting provider. The book is especially useful for beginners to get to grips with the bare bones of the framework needed to start developing Angular apps. By the end of this book, you’ll not only be able to create Angular applications with TypeScript from scratch but also enhance your coding skills with best practices.
Table of Contents (19 chapters)
1
Section 1: Getting Started with Angular
4
Section 2: Components – the Basic Building Blocks of an Angular App
9
Section 3: User Experience and Testability
15
Section 4: Deployment and Practice

Testing pipes

As we learned in Chapter 4, Enhance Components with Pipes and Directives, a pipe is a TypeScript class that implements the PipeTransform interface. It exposes a transform method that is usually synchronous, which means that it is straightforward to test. Let's create a simple pipe that converts a comma-separated string into a list:

list.pipe.ts

import { Pipe, PipeTransform } from '@angular/core';
@Pipe({
  name: 'list'
})
export class ListPipe implements PipeTransform {
  transform(value: string): string[] {
    return value.split(',');
  }
}

Writing a test for it is really simple. The only thing that we need to do is to instantiate an object of ListPipe and verify the outcome of the transform method with some mock data:

it('should return an array', () =>&...