Now, let's jump to the DeveloperDetails definition. In your working directory, create a file called developer_details.ts and enter the following content:

import {Component} from '@angular/core';
import {ActivatedRoute} from '@angular/router';
import {Developer} from './developer';
import {DeveloperCollection} from './developer_collection';
import {DeveloperBasicInfo} from './developer_basic_info';
import {DeveloperAdvancedInfo} from './developer_advanced_info';

import 'rxjs/add/operator/take';

@Component({
  selector: 'dev-details',
  template: `...`,
})
export class DeveloperDetails {
  public dev: Developer;

  constructor(private route: ActivatedRoute,
    private developers: DeveloperCollection) {}

  ngOnInit() {
    this.route.params.take(1)
     .subscribe((params: any) => {
       this.dev = this.developers.getUserById(parseInt(params['id']));&...