Angular 7可观察的等待变量为false

Question

The following observable:

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { CookieService } from 'ngx-cookie-service';
import { Observable } from 'rxjs';

@Injectable()
export class AuthService {
    readonly loginUrl = <login_url>;
    readonly authStatusUrl = <auth_status_url>;
constructor(private http: HttpClient, private cookieService: CookieService) {}

loggingIn = false;

login(username: string, password: string) {
    this.loggingIn = true;
    const creds = {
        username: username,
        password: password
    };
    this.http
    .post<any>(this.loginUrl, creds, {})
    .subscribe(
        data => this.onLoginSuccess(data),
        error => this.onLoginFail(error));
}

handleAuth(): Observable<any> {

    const token = this.cookieService.get('token');
    const refresh = this.cookieService.get('refresh');

    // should wait for loggingIn to be false
    return this.http
        .post<any>(this.authStatusUrl, { }, {
            headers: {
                token: token,
                refresh: refresh
            }
        });
}

public onLoginSuccess(data) {
    this.loggingIn = false;
    this.cookieService.set('token', data.access_token);
    this.cookieService.set('refresh', data.refresh_token);
}

onLoginFail(err) {
    console.log('Faild to login');
    this.loggingIn = false;
}

}

should not be executed until a local variable is false.

I read that this should be done using Promises and async function call with await operator, but I could not find something that will poll for the variable value, only 'wait for some time and the resolve'.

The main idea is to call handleAuth and internally it should assure that login is not in progress, by waiting for the local variable (or something to happen)

Answer 1

You can use a setter on the local variable for this purpose :

private _localVariable;


set localVariable(value) {
  this._localVariable = value;
  if(this._localVariable) {
   //call your function here.
  }
}

Answer 2

您可以做的是使loggingIn为Subject ，将“ done”事件推送到loggingIn ，然后将flatMap loggingIn送到http.post 。