What is the best way to establish communication with the root component in Angular?

Question

What is the best way to establish communication with the root component in Angular?

I have implemented a modal in the root component that can be triggered from anywhere. However, I am facing a dilemma on how the bottom component can communicate with the top component without excessive use of callback functions.

Root Component

<container></container>
<modal hide="true"></modal>

Container Component

<another-container></another-container>

Another Container Component

<child-that-trigger-modal></child-that-trigger-modal>

Essentially, I am looking for a simple and elegant solution for the bottom component (child-that-trigger-modal) to communicate with the top component (root) that contains the modal, without the need for excessive data passing and callback functions.

angular typescript

Answer 1

Answer №1

One notable feature in Angular 2 is that events emitted by the EventEmitter do not bubble (as of the posting date of this answer).

To facilitate communication between components, a shared service can be utilized.

// File: app/shared.service.ts

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

import { Subject } from 'rxjs/Subject';

@Injectable()
export class SharedService {

  notify$ = new Subject<any>();

  constructor() { }

  notify(obj) {
      this.notify$.next(obj);
  }

}

By creating an Observable and a shared service, a single instance of the service can be shared across all components.

To send data, you can utilize the .notify() function, for example:

export class ChildThatTriggerModalComponent implements OnInit {

  constructor(private sharedService: SharedService) { }

  notifyParent() {
      this.sharedService.notify({id: 1, name: 'John'});
  }

  ngOnInit() { }

}

To listen for any changes, subscribing to the observable is essential, for instance:

export class ContainerComponent implements OnInit {

  constructor(private sharedService: SharedService) {
    this.sharedService.notify$.subscribe(data => console.log(data));
  }

  ngOnInit() { }

}

Answer 2

One notable feature in Angular 2 is that events emitted by the EventEmitter do not bubble (as of the posting date of this answer).

To facilitate communication between components, a shared service can be utilized.

// File: app/shared.service.ts

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

import { Subject } from 'rxjs/Subject';

@Injectable()
export class SharedService {

  notify$ = new Subject<any>();

  constructor() { }

  notify(obj) {
      this.notify$.next(obj);
  }

}

By creating an Observable and a shared service, a single instance of the service can be shared across all components.

To send data, you can utilize the .notify() function, for example:

export class ChildThatTriggerModalComponent implements OnInit {

  constructor(private sharedService: SharedService) { }

  notifyParent() {
      this.sharedService.notify({id: 1, name: 'John'});
  }

  ngOnInit() { }

}

To listen for any changes, subscribing to the observable is essential, for instance:

export class ContainerComponent implements OnInit {

  constructor(private sharedService: SharedService) {
    this.sharedService.notify$.subscribe(data => console.log(data));
  }

  ngOnInit() { }

}

Answer 3

Answer №2

My recommendation is to decouple the modal from the root component. Instead, consider making the modal a separate service that can be used independently or with the root component if necessary.

Here's how you can do it:

Inject the modal service into the root component only if required.
Ensure that the same instance of the modal service is injected into the child component that triggers it. Make sure it's a singleton instance, declared only once, for example in your app.module file.

Answer 4

My recommendation is to decouple the modal from the root component. Instead, consider making the modal a separate service that can be used independently or with the root component if necessary.

Here's how you can do it:

Inject the modal service into the root component only if required.
Ensure that the same instance of the modal service is injected into the child component that triggers it. Make sure it's a singleton instance, declared only once, for example in your app.module file.

What is the best way to establish communication with the root component in Angular?

Answer №1

Answer №2

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