angular - 如何在 Angular 6/RxJS 6 中处理 http.get() 的结果？

Question

我正在尝试将应用程序从 Angular 5 升级到 Angular 6，但无法弄清楚如何使用 RxJS 的新语法。这是我尝试迁移的代码:

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

@Injectable()
export class SearchService {
  constructor(private http: HttpClient) {}

  getAll() {
    return this.http.get('assets/data/people.json');
  }

  search(q: string): Observable<any> {
    if (!q || q === '*') {
      q = '';
    } else {
      q = q.toLowerCase();
    }
    return this.getAll().map((data: any) => {
      const results: any = [];
      data.map(item => {
        // check for item in localStorage
        if (localStorage['person' + item.id]) {
          item = JSON.parse(localStorage['person' + item.id]);
        }
        if (JSON.stringify(item).toLowerCase().includes(q)) {
          results.push(item);
        }
      });
      return results;
    });
  }

  get(id: number) {
    return this.getAll().map((all: any) => {
      if (localStorage['person' + id]) {
        return JSON.parse(localStorage['person' + id]);
      }
      return all.find(e => e.id === id);
    });
  }

  save(person: Person) {
    localStorage['person' + person.id] = JSON.stringify(person);
  }
}

我知道导入应该更改为:

import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';

现在您应该使用 pipe() 而不是 map()，但我在弄清楚如何使用时遇到了问题。如果像下面这样简单那就太好了，但似乎并非如此。

    return this.getAll().pipe(
      map(data: any) => {
        const results: any = [];
        data.map(item => {
          // check for item in localStorage
          if (localStorage['person' + item.id]) {
            item = JSON.parse(localStorage['person' + item.id]);
          }
          if (JSON.stringify(item).toLowerCase().includes(q)) {
            results.push(item);
          }
        });
        return results;
    }));

Answer 1

您在 map(data:any) => {} 处缺少括号。这应该有效:

return this.getAll().pipe(
    map((data: any) => {
        const results: any = [];
        data.map(item => {
            // check for item in localStorage
            if (localStorage['person' + item.id]) {
                item = JSON.parse(localStorage['person' + item.id]);
            }
            if (JSON.stringify(item).toLowerCase().includes(q)) {
                results.push(item);
            }
        });
        return results;
    }
    )
);

您可以以更具可读性和功能性的方式执行此操作，如下所示 - 使用 Array.prototype.map 函数来实现其应有的用途并添加过滤器:

return this.getAll().pipe(
    map(
        data => data
             .map(item => !!localStorage['person' + item.id]
                ? JSON.parse(localStorage['person' + item.id])
                : item)
             .filter(item => JSON.stringify(item).toLowerCase().includes(q))
    )
);