Angular Custom Directives

Introduction

In Angular, a directive is a class with a @Directive decorator that can be used to add behavior to any element on the page. One of the powerful features of Angular is the ability to create your own custom directives to add your own custom behavior to elements.

Syntax

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

@Directive({
  selector: '[appCustomDirective]'
})
export class CustomDirective {
  //logic
}

Example

<div appCustomDirective>Custom directive example</div>

Output

The output of the above example will be a custom directive applied to the div element.

Explanation

The @Directive decorator is used to define a new directive. The selector property specifies the CSS selector that identifies the element, or elements, on which the directive is applied. The directive class encapsulates the behavior that is added to the element.

Use

Custom directives in Angular can be used for a variety of things like:

• Performing custom validation on form inputs.
• Creating reusable visual components.
• Attaching special behavior to elements.
• Modifying the DOM.

Important Points

• Directives can change the behavior or appearance of DOM elements.
• Angular provides several built-in directives (such as *ngIf, *ngFor, etc.) that can be used directly in templates.
• Custom directives can be created with the @Directive decorator.
• Custom directives can be used to add or modify the behavior of any element on the page.
• Directives can also be used to modify the structure of the DOM.

Summary

Angular custom directives are a powerful feature that allows you to create your own behavior that can be attached to any element on the page. By creating a new class with the @Directive decorator, you can encapsulate behavior and add it to the element of your choosing. This provides a great deal of flexibility when creating reusable components in your application.