How do you inject one service into another?

Beginner

Answer

Services can depend on other services through constructor injection:

@Injectable({
  providedIn: 'root'
})
export class LoggerService {
  log(message: string): void {
    console.log(message);
  }
}

@Injectable({
  providedIn: 'root'
})
export class DataService {
  constructor(private logger: LoggerService) {}

  getData(): any[] {
    this.logger.log('Getting data...');
    return [];
  }
}

Important: Avoid circular dependencies where Service A depends on Service B and Service B depends on Service A.