Ways to invoke a function from one component in another

Having created two components - navbar and login, I am attempting to call a function from the navbar component in the login component. Thus far, my attempts have been unsuccessful...

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

@Component({
    selector: 'header-Navbar',
    templateUrl: './app/navbar/navbar.html',
})
export class Navbar implements OnInit  {

    constructor(public router: Router) {

    } 
    get(){
         if (this.user == null) {
            this.showstartupbuttons = true;
            this.showsicons = false;
        }
        else {
            this.username = this.user.username;
            this.showsicons = true;
            this.showstartupbuttons = false; 
        }
    }

In my login.ts file:

import {Component, OnInit} from '@angular/core';
@Component({
    templateUrl: './app/login/login.html',
    providers:[Navbar]
})
export class Login implements onInit{
    ckeditorContent:any;
    constructor(public navbar:Navbar) {}
      ngOnInit(){
           this.navbar.get();
      }

I have included providers, but I am uncertain about this process. Could someone please suggest a solution?

Answer №1

To streamline component interactions, consider using a specialized service like the one below.

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

@Injectable()
export class NavService{
    private source = new Subject<any>();
    data$ = this.source.asObservable();

    triggerNavUpdate(){
        this.source.next(null);
    }
}

It is crucial to inject this service into both the navigation bar and login components. Keep in mind that services are singleton instances for each provider. Therefore, ensure that a common component provides access to this service for both components.

In your navigation bar component:

constructor(public router: Router, navService: NavService) {
    navService.data$.subscribe(param => {this.update();})
}

You can invoke this functionality in your login component with the following code snippet:

constructor(public navbar:Navbar, private navService: NavService) {}
      ngOnInit(){
           this.navService.triggerNavUpdate();
      }

For further information on component communication, check out this resource.

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