如何在Angular中访问可变嵌套JSON数据模型

interface MyData {
  id: number;
  name: string;
  children?: MyData[];
}

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';

@Injectable({
  providedIn: 'root'
})
export class DataService {
  private dataUrl = 'assets/data.json';

  constructor(private http: HttpClient) { }

  getData(): Observable<MyData[]> {
    return this.http.get<MyData[]>(this.dataUrl);
  }
}

import { Component, OnInit } from '@angular/core';
import { DataService } from 'path-to-data-service';

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css']
})
export class MyComponent implements OnInit {
  data: MyData[];

  constructor(private dataService: DataService) { }

  ngOnInit() {
    this.dataService.getData().subscribe(data => {
      this.data = data;
    });
  }
}

<ul>
  <li *ngFor="let item of data">
    {{ item.name }}
    <ul *ngIf="item.children">
      <li *ngFor="let child of item.children">
        {{ child.name }}
      </li>
    </ul>
  </li>
</ul>