CODEWITHSUNDEEP
angularangular-servicescircular-dependencyangular11
Aishwarya Gharde
Aishwarya Gharde

Reputation: 1

Circular dependency Error in /turbo_modules/@angular/[email protected]/bundles/compiler.umd.js (2845:21) Can't resolve all parameters for BService: (?)

A-Service.component.ts

` import { Injectable, Inject } from '@angular/core'; import { BService } from './BService';

@Injectable({
  providedIn: 'root',
})
export class AService {
  constructor(private bService: BService) {}

  getMessageFromB(): string {
    return this.bService.getMessage();
  }

  getMessage(): string {
    return 'Message from AService';
  }
}
B-service.component.ts
---------------------
import { Injectable, Inject } from '@angular/core';
import { AService } from './AService';

@Injectable({
  providedIn: 'root',
})
export class BService {
  constructor(private aService: AService) {}

  getMessageFromA(): string {
    return this.aService.getMessage();
  }

  getMessage(): string {
    return 'Message from BService';
  }
}
app.component.ts
-------------------
@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css'],
  providers: [AService, BService],
})
export class AppComponent {
  messageFromB: string = '';
  messageFromA: string = '';

  constructor(
    private readonly aService: AService,
    private readonly bService: BService
  ) {}

  ngOnInit() {
    this.messageFromB = this.aService.getMessageFromB();
    this.messageFromA = this.bService.getMessageFromA();
  }
}
HTML
------------------
<p>{{ messageFromB }}</p>    
<p>{{ messageFromA }}</p>    `

When I run this I get the below error
---------------------------------------------
Error in /turbo_modules/@angular/[email protected]/bundles/compiler.umd.js (2845:21)
Can't resolve all parameters for BService: (?).

I am trying to print the message using HTML as below. I am expecting HTML to print the message , but as my services are having circular dependency I am getting the said error

Upvotes: 0

Views: 33

Answers (1)

Gykonik
Gykonik

Reputation: 668

As Ajeet Shah already pointed out, you've got a circular dependency, meaning AService depends on BService and vice versa, which doesn't make sense and causes a loop/circle.

If you need some sort of mutual connection, then I'd recommend introducing another CService that handles the "communication" and breaks out of the loop. So AService -> CService and Bservice -> CServiceS

Upvotes: 0

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