Book Image

Learning Angular - Fourth Edition

By : Aristeidis Bampakos, Pablo Deeleman
5 (1)
Book Image

Learning Angular - Fourth Edition

5 (1)
By: Aristeidis Bampakos, Pablo Deeleman

Overview of this book

As Angular continues to reign as one of the top JavaScript frameworks, more developers are seeking out the best way to get started with this extraordinarily flexible and secure framework. Learning Angular, now in its fourth edition, will show you how you can use it to achieve cross-platform high performance with the latest web techniques, extensive integration with modern web standards, and integrated development environments (IDEs). The book is especially useful for those new to Angular and will help you to get to grips with the bare bones of the framework to start developing Angular apps. 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. Updated for Angular 15, this new edition covers lots of new features and tutorials that address the current frontend web development challenges. You’ll find a new dedicated chapter on observables and RxJS, more on error handling and debugging in Angular, and new real-life examples. 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 (17 chapters)
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Validating controls in a reactive way

We have already learned how to apply validation to the template of a form. We used the required attribute in the Using reactive patterns in Angular forms section to indicate that an input control needs to have a value. In reactive forms, the source of truth is our form model, so we need to be able to define validation rules when building the FormGroup instance. To add validation rules, we use the second parameter of the FormControl constructor:

  1. Open the product-create.component.ts file and import the Validators artifact from the @angular/forms npm package:
import { FormControl, FormGroup, Validators } from '@angular/forms';
  1. Modify the declaration of the productForm property so that each FormControl instance passes Validators.required as a second parameter:
productForm = new FormGroup({
  name: new FormControl('', {
    nonNullable: true,
    validators: Validators...