I am coding an API with Angular2 and NodeJS, I am implementing services for my ِAPI that is supposed to get a list of tasks and display it. Here is the task service:

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

import {Http, Headers} from '@angular/http';

import 'rxjs/add/operator/map';



@Injectable()

export class TaskService{

  constructor(private http:Http){

    console.log('Task Service Initialized...');

  }

  getTasks(){

    return this.http.get('http://localhost:3000/api/tasks')

      .map(res => res.json());

  }

}

For my getTask function (correct me if I am wrong) the .map() function takes my response and formats it in an array of values.
Here is now, the task components that uses the task service:

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

import {TaskService} from '../../services/task.service';



@Component({

  moduleId: module.id,

  selector: 'tasks',

  templateUrl: 'tasks.component.html',

})

export class TasksComponent  {

  constructor(private taskService:TaskService){

    this.taskService.getTasks()

      .subscribe(tasks =>{

        console.log(tasks);

    })

  }

}

I would like to understand what this .subscribe() function does and I can't find any relevant information.