Modify Child object With data from Parent ObjectV3

// Base Task Model
export class Task {
  constructor(
      public goal_id: string,
      public name: string,
      public description: string,
      public priority: string,
      public taskDate: string,
  ) {}
}


// Base Goal Model
export class Goal {
  constructor(
      public name: string,
      public isMainGoal: boolean,
      public details: string,
      public category: string,
      public lifeArea: string,
      public creationDate: string,
      public priority: string,
      public endDate: Date,

  ) {}
}



// Task Service

  tasksCollection():Observable<any> {
    return this.fetchTasks()
      .pipe(
        map(response => {
          const tasksArray = [];
          for (const key in response) {
            if (response.hasOwnProperty(key)) {
              tasksArray.push({ ...response[key], id: key });
            }
          }
          return tasksArray;
        })
      );
  }

// Goal Service

getGoalById(id:string):Observable<any> {
    return this.goalsCollection()
    .pipe(
      map(response => {
        response = response.filter((v:any) => v.id === id);
        return response;
      })
    )
}


// How, in Dashboard Component, modify each Task Item from tasksCollection so that new Key(goalCategory) and Value
// being the category name from queried Goal Object (queried Goal based on foreign key) is added to each Task ?




// Dashboard Component
export class DashboardComponent implements OnInit {

    goalCategory!:any; // parameter to which new value is supposed to be assigned with the help of getGoalCategory method on each iteration inside tasksArray
    
    ngOnInit() {
        // Fetch Tasks
        this.tasksService.tasksCollection()
          .pipe(
            map(tasksArray => {
              tasksArray = tasksArray.map((item:any) => {
                this.getGoalCategory(item);  // method which is supposed to assign new value to this.goalCategory parameter
                return {
                  ...item,
                  goalCategory: this.goalCategory // -> new key with value from Goal!
                }
              })
              return tasksArray;
            })
        )
      // do każdego elementu tablicy dodaj nowy obiekt z kategorią rodzica
      .subscribe(
        tasks => {
          console.log(tasks);
        }
      )
    }
    
    // Helper Method
    getGoalCategory(item:any) {
    	  this.goalsService.getGoalById(item.goal_id).subscribe(d => {
          this.goalCategory = d[0].category;
          // IMPORTANT!
          // this.goalCategory is accessible here, it works here, however 'this.goalCategory' returns 'undefined' 
          // in the code above inside ngOnInit in Dashboard // Component 
        })
    }

}