例子
import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators, FormControl..., AbstractControl } from '@angular/forms';
import { concat, merge, zip, combineLatest, race } from 'rxjs.../app.component.css']
})
export class AppComponent implements OnInit {
form: FormGroup;
constructor...]="form">
username:
hobby:...再输出成一个值
// 这个有个问题是只有合并的元素都产生值才会输出内容，所以在上面使用startWith赋初始化值
combineLatest(username$, status$)
