Angular2:在调用方法之前获取服务的属性值

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

@Injectable({
  providedIn: 'root'
})
export class DataService {
  data: any;

  constructor() {
    this.data = { key: 'value' }; // 初始化数据
  }

  fetchData() {
    // 模拟异步获取数据
    return new Promise((resolve) => {
      setTimeout(() => {
        this.data = { key: 'new value' };
        resolve(this.data);
      }, 1000);
    });
  }
}

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

@Component({
  selector: 'app-my-component',
  template: `<div>{{ data | json }}</div>`
})
export class MyComponent implements OnInit {
  data: any;

  constructor(private dataService: DataService) {}

  ngOnInit() {
    // 在组件初始化时获取数据
    this.data = this.dataService.data;
  }

  async updateData() {
    // 调用服务方法并等待数据更新
    const newData = await this.dataService.fetchData();
    this.data = newData;
  }
}

async updateData() {
  // 等待数据更新完成
  const newData = await this.dataService.fetchData();
  this.data = newData;
}