Transfer information between components using input and output bindings

I have been attempting to pass data from the msg component to the filter component. Both components are injected in the main component, but despite many attempts, I have been unable to achieve this. I am unsure whether to use @input or @output.

main.component.html

<app-msg></app-msg> // Data is being passed from this component to the filter component
<app-filter (filterMSg)='msg'></app-filter>

filter.component.ts

filterMSg:string = '';

msg.component.ts

msg:string = 'text from msg component';

Answer №1

It seems like you are trying to pass a message from your msg component to your filter component, is that correct?

If so, here is what you need to do:

  1. Retrieve the data from your msg component in your main component using an @Output().
  2. Pass the received data from the main component to your filter component using an @Input().

Step 1

In your msg.component.ts :

export class MsgComponent {
  @Output() messageEmitter: EventEmitter<string> = new EventEmitter<string>();

  public emitMessage(message: string): void {
    this.messageEmitter.emit(message);
  }
}

Here, you create an EventEmitter that will be triggered by the method emitMessage() when you want it to be passed to the main component.

In your main.component.ts :

export MainComponent {
  public message: string = '';

  public getMessage(message: string): void {
    this.message = message;
  }
}

You create a method in your main component to retrieve the value of the @Output().

In your main.component.html :

<app-msg (messageEmitter)="getMessage($event)"></app-msg>

You use the method defined in your main component to retrieve the message when the @Output() is triggered in the child component.

Step 2

In filter.component.ts :

export class FilterComponent {
  @Input() message: string;
}

You create an @Input() that will receive the data sent by the parent (the main component).

In main.component.html :

<app-filter [message]="message"></app-filter>

You pass the message from the main component (after the '=' sign) to the child component's attribute message (inside brackets).

Answer №2

Your requirements may not be fully clear at the moment.

Here is a basic example of how a child component can send data to its parent:

export class ChildComponent {

  @Output() newDataEvent = new EventEmitter<string>();

  addNewData(value: string) {
    this.newDataEvent.emit(value);
  }
}

Similarly, here is an example of a component that receives data from its parent:

import { Component, Input } from '@angular/core'; // Importing Input is necessary
export class ParentDetailComponent {
  @Input() item = ''; // Use @Input() to specify the property will receive data from parent
}

Remember to check out Angular's documentation on inputs and outputs for more information!

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