Angular Reactive Forms E-Book

Abdelfattah Ragab

• Herausgeber: tredition
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 17

Veröffentlichungsjahr: 2024

Beschreibung

Welcome to the book "Angular Reactive Forms". In this book, I explain everything you need to know about reactive forms. With reactive forms, you define the form model directly in the component class. This is an elegant way to deal with form fields that gives you full control over all aspects of reading and updating values and performing all kinds of validations. This way you can easily create and edit dynamic forms from your component class. In this book, I will show you how to create forms, update values, perform validations, display error messages, work with hierarchical groups and form arrays, upload files, preview images, and much more. By the end of this book, you will be confident working with forms in your Angular application and be able to handle all kinds of scenarios. Let us get started.

Leseprobe

Angular Reactive Forms

Everything you need to know

Abdelfattah Ragab

Introduction

Welcome to the book “Angular Reactive Forms”.

In this book, I explain everything you need to know about reactive forms.

With reactive forms, you define the form model directly in the component class. This is an elegant way to deal with form fields that gives you full control over all aspects of reading and updating values and performing all kinds of validations.

This way you can easily create and edit dynamic forms from your component class.

In this book, I will show you how to create forms, update values, perform validations, display error messages, work with hierarchical groups and form arrays, upload files, preview images, and much more.

By the end of this book, you will be confident working with forms in your Angular application and be able to handle all kinds of scenarios.

Let us get started.

Overview of reactive forms

Reactive forms provide a model-driven approach to handling form inputs whose values change over time.

Reactive forms use an explicit and immutable approach to manage the state of a form at a given time. Each change to the form state results in a new state, preserving the integrity of the model between changes. Reactive forms are based on observable streams, where the inputs and values of the form are provided as streams of input values that can be accessed synchronously.

Import the ReactiveFormsModule

To use reactive form controls, import ReactiveFormsModule from the @angular/forms package and add it to your imports array.

Simple Form

Let's start with a simple login form where you ask for the user's email and password.

In the imports array of the standalone component, import the ReactiveFormsModule as follows:

import { Component } from '@angular/core';

import { ReactiveFormsModule } from '@angular/forms';

@Component({

selector: 'app-login',

standalone: true,

imports: [ReactiveFormsModule],

templateUrl: './login.component.html',

styleUrl: './login.component.css',

})

export class LoginComponent {}

Now we declare a form with email and password fields:

import { Component, OnInit } from '@angular/core';

import { FormBuilder, FormGroup, ReactiveFormsModule } from '@angular/forms';

@Component({

selector: 'app-login',

standalone: true,

imports: [ReactiveFormsModule],