Understanding @Injectable and @Inject Decorators in Angular

In Angular, decorators are used to attach metadata to classes, methods, properties, and parameters. Two commonly used decorators are @Injectable and @Inject. While they might seem similar, they serve different purposes. Let’s dive into their differences and see how they are used with examples.

@Injectable Decorator

The @Injectable decorator is used to mark a class as available for dependency injection. It tells Angular's dependency injection system that the class can be injected as a dependency into other classes.

Decorators in Angular

There are several important concepts in Angular, and Decorators are an important concept to learn when you are working Angular. Decorators in Angular are a powerful and essential feature used to enhance and modify the behavior of classes, methods, and properties. Through this post we will learn about decorators, its types and how it is being used in real time applications.

What are Decorators?

Decorators are functions that are invoked with a prefixed @ symbol.Basically, a decorator provides configuration metadata that determines how the component, class or a function should be processed, instantiated and used at runtime.Decorators are applied to classes, class properties, and class methods using the following syntax:

@DecoratorName(arguments)

Angular comes with several built-in decorators, and you can also create custom decorators to extend or modify the behavior of your application.

Angular - Utilizing the @ViewChild Decorator in Angular for Enhanced Component Interaction

Angular, a robust web application framework, offers developers a vast array of tools and features to boost productivity. One such feature is the @ViewChild decorator, which facilitates the access of child components, directives, or DOM elements within Angular components. In this article, we will explore the capabilities of @ViewChild and delve into its practical applications for interacting with child elements and components in your Angular applications.

Understanding @ViewChild:

The @ViewChild decorator enables developers to obtain references to child components, directives, or DOM elements residing within the template of a parent component. It grants access to properties and methods of the child component, facilitates interaction with the child directive, and allows direct manipulation of the DOM element.

Syntax: The syntax for implementing the @ViewChild decorator is as follows:

@ViewChild(selector, options) propertyName: Type;

1. The selector represents the CSS selector or component class used to identify the child element/component.
2. The options parameter is optional and allows for the specification of additional view query options.

Example 1: Accessing a Child Component

Let's consider a scenario where we have a parent component, ParentComponent, that includes a child component named ChildComponent. To access the child component from the parent component, we can utilize the @ViewChild decorator as illustrated below:

Angular - Understanding @Input and @Output Decorators

Angular is a widely-used framework for creating web applications, offering powerful features for component-based development. Two important decorators in Angular are '@Input' and '@Output'. These decorators facilitate communication between components. In this post, we'll explore these decorators and learn how to utilize them effectively.

@Input Decorator

The '@Input' decorator is employed to define an input property on a component, enabling the flow of data from a parent component to a child component. By utilizing '@Input', you can bind values to properties within a child component, allowing for dynamic data exchange.

To define an input property, simply add the '@Input()' decorator above the property declaration within the child component. Here's an example:

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

@Component({
  selector: 'child-component',
  template: `Child Component: {{ childProperty }}`
})
export class ChildComponent {
  @Input() childProperty: string;
}