javascript - Angular 7 map 运算符无法与 httpClient Observable 一起使用

Question

添加 map 运算符后，我得到“未定义”

Angular 版本:7

map 导入:

import { map } from 'rxjs/operators';

带有 map :

this.restaurantService.getRestaurants().pipe(map((restaurant:any) => restaurant.name)).subscribe((restaurants) => {
  console.log(restaurants); // undefined
});

Not necessary "name" field is returning undefined at any field

没有 map

this.restaurantService.getRestaurants().subscribe((restaurants) => {
  console.log(restaurants); // [{...,name: 'lorem'},{...},...]
});

服务:

  getRestaurants(): Observable<_Restaurant[]> {
    return this.get(api.restaurants) as Observable<_Restaurant[]>;
  };

我在 map 操作符中记录了餐厅，我得到了一个应该是对象的数组

 .pipe(map(restaurant => {
    console.log(restaurant); //[{},{}] !!
    return restaurant.name;
  }))

知道为什么我会得到未定义的结果吗？

Answer 1

this.restaurantService
    .getRestaurants()
    .pipe(map((restaurants:any[]) => restaurants.map(restaurant => restaurant.name)));