On And Broadcast In Angular

Angular is a popular and powerful front-end framework that simplifies the process of building dynamic web applications. One of the key features in Angular is the `@Output` decorator, which allows you to create custom events and broadcast data from child components to parent components.

When working with Angular components, you might often come across scenarios where you need to pass data from a child component to a parent component. This is where the `@Output` decorator comes in handy. By using `@Output`, you can emit custom events from the child component and subscribe to these events in the parent component.

To create a custom event in Angular, you first need to import the `EventEmitter` and `Output` symbols from `@angular/core` in your child component. Here's an example of how you can define an output property in a child component:

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

@Component({
  selector: 'app-child',
  template: `
    <button>Send Data</button>
  `
})
export class ChildComponent {
  @Output() dataEvent = new EventEmitter();

  emitData() {
    this.dataEvent.emit('Hello from child component!');
  }
}

In this example, we have a `ChildComponent` that defines an `@Output` property named `dataEvent`. We have also created a method `emitData()` that emits the data we want to pass to the parent component using the `emit()` method of the `EventEmitter`.

Next, in the parent component, you can listen to the custom event emitted by the child component by binding to the event using the event handler syntax. Here's how you can subscribe to the custom event in the parent component:

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

@Component({
  selector: 'app-parent',
  template: `
    
  `
})
export class ParentComponent {
  receiveData(data: string) {
    console.log('Data received in parent component: ', data);
  }
}

In the `ParentComponent`, we use the `dataEvent` event binding on the `app-child` element and call a method `receiveData($event)` when the event is emitted from the child component. The `$event` variable contains the data emitted by the child component.

By leveraging the `@Output` decorator and `EventEmitter`, you can establish communication between parent and child components in Angular applications. This enables you to create interactive and data-driven UI components that respond dynamically to user interactions.

In conclusion, mastering the concept of `@Output` and event emitters in Angular is essential for building robust and interactive web applications. By understanding how to broadcast data from child to parent components, you can enhance the user experience and create more dynamic and engaging web applications.