FormControl basics in Angular - Mini Project: Build & Apply

FormControl basics

📖 Scenario: You are building a simple Angular form to collect a user's name. You want to use Angular's FormControl to manage the input field.

🎯 Goal: Create an Angular standalone component that uses FormControl to bind an input field for the user's name and display the current value below it.

📋 What You'll Learn

Create a FormControl instance named nameControl with an initial empty string value.

Add a configuration variable maxLength set to 20 to limit the input length.

Bind the nameControl to an input field using Angular's reactive forms syntax.

Display the current value of nameControl below the input field in the template.

💡 Why This Matters

🌍 Real World

Forms are everywhere on websites and apps. Using FormControl helps manage user input easily and reactively.

💼 Career

Understanding FormControl is essential for Angular developers to build interactive and user-friendly forms.

1

Create the FormControl instance

In the component class, create a FormControl instance named nameControl and initialize it with an empty string ''.

Angular

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

@Component({
  selector: 'app-name-input',
  standalone: true,
  imports: [],
  template: `
    
  `
})
export class NameInputComponent {
  // Create FormControl named nameControl with initial value ''
  
}

Need a hint?

Use new FormControl('') to create the control with an empty string.

2

Add maxLength configuration

Add a number variable named maxLength in the component class and set it to 20.

Angular

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

@Component({
  selector: 'app-name-input',
  standalone: true,
  imports: [],
  template: `
    
  `
})
export class NameInputComponent {
  nameControl = new FormControl('');
  // Add maxLength variable set to 20
}

Need a hint?

Just add maxLength = 20; inside the class.

3

Bind FormControl to input field

In the component decorator, add imports with FormControl dependencies and update the template to include an <input> element bound to nameControl using [formControl]. Also, add the maxlength attribute bound to maxLength.

Angular

import { Component } from '@angular/core';
import { FormControl, ReactiveFormsModule } from '@angular/forms';

@Component({
  selector: 'app-name-input',
  standalone: true,
  imports: [ReactiveFormsModule],
  template: `
    
  `
})
export class NameInputComponent {
  nameControl = new FormControl('');
  maxLength = 20;
}

Need a hint?

Import ReactiveFormsModule and add it to imports. Use [formControl]="nameControl" on the input and bind maxlength with [attr.maxlength]="maxLength".

4

Display current FormControl value

In the template, below the input field, add a <p> element that shows the text Your name is: followed by the current value of nameControl.value using Angular interpolation.

Angular

import { Component } from '@angular/core';
import { FormControl, ReactiveFormsModule } from '@angular/forms';

@Component({
  selector: 'app-name-input',
  standalone: true,
  imports: [ReactiveFormsModule],
  template: `
    
    
  `
})
export class NameInputComponent {
  nameControl = new FormControl('');
  maxLength = 20;
}

Need a hint?

Use Angular interpolation {{ nameControl.value }} inside a paragraph below the input.