如何在不停止排队调用的情况下使异步调用并行

Question

我有 50 个科目，我发送 50 个并行调用，每个科目返回 1 个或多个学生数据 例如：如果我发送一个 subjectId，this.subjectService.getStudentsData(subjectId) 它返回学生数据：

[
{StudentId:1,
"FirstName":'firstName', 
"ListOfSubjects":[{Subjectid:1,SubjectName:'Maths', .....somedata:[{1:a,2:b...}, {3:y,2:x...}]}},

{
StudentId:2, 
FirstName:secondName, 
.
.
ListOfSubjects:[
{Subjectid:1,SubjectName:'Maths', .....somedata:[{c:1,d:2...}, {a:y,b:x...}]}}]

现在我需要在通过用户数据获取用户时进行绑定，但完成所有服务调用需要 15 分钟

我用的是

const requests: any = subjectIds.map(id => {   
            const t: any = {...data};
            t.SubjectId = [id];
          return this.studentService.getStudentsData(t);
        });

Answer 1

就像mamichels 说你可以使用forkJoin，但我记得读过forkJoin 最多只能做6 个，除非你可以使用dictionary。

我愿意：

const requests: any = combineLatest(...subjectIds.map(id => this.studentService.getStudentData(id) /* you know what should go in the argument */)
...
requests.subscribe(responseArray => console.log(responseArray));

==========================编辑==================== =====

要获得每个请求完成的通知，我会使用merge

import { merge } from 'rxjs';

const requests: any = merge(...subjectIds.map(id => this.studentService.getStudentData(id));

....
requests.subscribe(response => { /* handle each response as it returns */ }));

================= 好吧，试试老派的方法================

for (let i = 0; i < subjectIds.length; i++) {
  this.studentService.getStudentsData(subjectIds[i].StudentId/* again, I am not sure what goes here as argument */).subscribe(
  response => {
    console.log(response);
  }
);
}