Inter-component communication within nested structures in Angular 2

Question

Inter-component communication within nested structures in Angular 2

Working on an Angular2 project that involves multiple nested components, I have successfully sent data from a child component to its immediate parent. However, when dealing with three levels of nesting, the question arises: How can I send or modify data across multiple parent components?

For instance, in the scenario depicted above, No 1 represents the message-center component. No 2 is the message-list component which is invoked within No 1 component's HTML using the selector < message-list [messageList]="mails" >.

No 3 portrays a message-detail component, with its parent being No 2. Now, if we delete a selected message from the Inbox within the No 3 component, that message should also be removed from the message-list component (No 2). Furthermore, in the No 1 component, the label "Deleted" should update to "Deleted(1)" as well. How can we propagate this change event to multiple parent components in a two-level nested child component such as No 3?

https://i.sstatic.net/TzcZR.png

javascript angular typescript components

Answer 1

Answer №1

If you're looking to incorporate a BehaviorSubject in a service, consider implementing it within a Message service. Don't forget to include the do rxjs operator when needed:

 @Injectable()
 export class MessageService {
     public $messages: BehaviorSubject<Message[]> = new BehaviorSubject<Message[]>([]);
     public getMessages() {
        const url = 'your url';
        return this.http.get(url).do(messages => this.$messages.next(messages));
     }
 }

To access your data in a component, inject the service and utilize the method as shown below:

 msgService.$messages.subscribe(messages => this.messages = messages); // update data each time next is called
 msgService.getMessages().subscribe(); // perform the http call

When deleting a message, simply update the list by using next:

const newList = this.messages.filter(message => message.id !== deletedMessage.id);
msgService.$messages.next(newList);

This will automatically update the data for you. Hopefully, this explanation proves helpful.

Answer 2

If you're looking to incorporate a BehaviorSubject in a service, consider implementing it within a Message service. Don't forget to include the do rxjs operator when needed:

 @Injectable()
 export class MessageService {
     public $messages: BehaviorSubject<Message[]> = new BehaviorSubject<Message[]>([]);
     public getMessages() {
        const url = 'your url';
        return this.http.get(url).do(messages => this.$messages.next(messages));
     }
 }

To access your data in a component, inject the service and utilize the method as shown below:

 msgService.$messages.subscribe(messages => this.messages = messages); // update data each time next is called
 msgService.getMessages().subscribe(); // perform the http call

When deleting a message, simply update the list by using next:

const newList = this.messages.filter(message => message.id !== deletedMessage.id);
msgService.$messages.next(newList);

This will automatically update the data for you. Hopefully, this explanation proves helpful.

Answer 3

Answer №2

By utilizing EventEmitter in component 3, I successfully carried out the notification task. To trigger an action in component 1 based on an event in component 3, I informed component 2 - the direct parent of component 3, which then passed on the notification to its parent component 1. Though it may seem a bit complicated, this approach actually simplifies the process.

Answer 4

By utilizing EventEmitter in component 3, I successfully carried out the notification task. To trigger an action in component 1 based on an event in component 3, I informed component 2 - the direct parent of component 3, which then passed on the notification to its parent component 1. Though it may seem a bit complicated, this approach actually simplifies the process.

Inter-component communication within nested structures in Angular 2

Answer №1

Answer №2

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