Angular 12 ConcatMap我该怎么做呢？

import { of } from 'rxjs';
import { concatMap, delay } from 'rxjs/operators';
import { ajax } from 'rxjs/ajax';

// 模拟一系列的请求ID
const requestIds = [1, 2, 3, 4];

// 发送请求的函数
const sendRequest = (id) => ajax.getJSON(`https://api.example.com/data/${id}`);

// 使用 concatMap 按顺序发送请求
of(...requestIds).pipe(
  concatMap(id => sendRequest(id).pipe(delay(1000))) // 延迟1秒模拟网络请求时间
).subscribe({
  next: response => console.log('Response:', response),
  error: err => console.error('Error:', err),
  complete: () => console.log('All requests completed.')
});

import { of } from 'rxjs';
import { concatMap, catchError } from 'rxjs/operators';
import { ajax } from 'rxjs/ajax';

const requestIds = [1, 2, 3, 4];

const sendRequest = (id) => ajax.getJSON(`https://api.example.com/data/${id}`);

of(...requestIds).pipe(
  concatMap(id => sendRequest(id).pipe(
    catchError(err => {
      console.error('Error in request', id, err);
      return of(null); // 返回一个空值或默认值，使流继续执行
    })
  ))
).subscribe({
  next: response => console.log('Response:', response),
  complete: () => console.log('All requests completed.')
});