相关疑难解决方法(0)

这是我的异步验证器它没有去抖时间,我该如何添加它？

static emailExist(_signupService:SignupService) {
  return (control:Control) => {
    return new Promise((resolve, reject) => {
      _signupService.checkEmail(control.value)
        .subscribe(
          data => {
            if (data.response.available == true) {
              resolve(null);
            } else {
              resolve({emailExist: true});
            }
          },
          err => {
            resolve({emailExist: true});
          })
      })
    }
}

1.它甚至得到了Angular的支持吗？看到这个开放的问题

2.如果是的话,什么是错在下面的代码

export class someClass{

    myForm:ControlGroup;

    constructor(public http:Http, public formBuilder:FormBuilder)
       this.myForm = formBuilder.group({
            ImageId: ["", Validators.required, this.asynValidator]
    });

    asyncValidator(control: Control): {[key: string]: any} {

        return new Promise (resolve => {

          let headers = new Headers();
          headers.append('Content-Type', 'application/json');

          this.http.get('http://localhost/ImageIdValidate?id='+ control.value, {headers:headers})
                .map(res => res.json())
                .subscribe(data => {
                    console.log(data);
                    if(data != null) {
                        resolve({"duplicate": true})
                    }
                    else resolve(null);      
                })
            });
        });
      }
    }

它甚至没有提出服务器请求.

我有一个注册表单,我想检查是否已经使用了用户名.为了达到这个目的,我现在正在使用承诺.我的注册组件如下所示:

import { Component, OnInit } from '@angular/core';
import { FormControl, FormBuilder, FormGroup, Validators } from '@angular/forms';
import { UserService } from '../shared/user.service'

@Component({
  selector: 'app-auth',
  providers: [],
  templateUrl: './auth.component.html',
  styleUrls: ['./auth.component.css']
})

export class AuthComponent implements OnInit {

  // Tabs for log in or sign up
  tab = 'signup';

  // Sign up form
  signUpForm: FormGroup;

  // Log in form
  logInForm: FormGroup;

  constructor(private formBuilder: FormBuilder, private ussr: UserService) {
     this.signUpForm = this.formBuilder.group({
       'username': [null, [
         Validators.required, Validators.minLength(4), Validators.maxLength(12), this.ussr.getUserNameFromServer
       ]], …