尝试更新可观察的.map()函数中的全局变量

Question

我当前正在尝试在map((函数中更新全局变量foundProfile。现在，我一半意识到这可能不是我应该做事的方式 - 但是我无法找出原因，如果有匹配，我也无法想到其他方法将变量设置为True。这是我当前的代码：

export class LoginComponent implements OnInit {
    private usernameTxt: string;
    private passwordTxt: string;
    private foundProfile: boolean;
    constructor(private router: Router, private page: Page, private loginService: LoginService, private profileService: ProfileService) {
        page.actionBarHidden = true;
    }
    ngOnInit() {
        this.usernameTxt = 'someUsername';
        this.passwordTxt = 'SomePassword321!';
        this.foundProfile = false;
    }
    getProfile(username: string, password: string) {
        return this.loginService.getProfiles()
        .map(
            profiles => profiles.filter(
                (profile => {
                    if(profile.email == username && profile.password == password) {
                        this.foundProfile = true; //Set to true so we know a profile has been found
                        return profile;
                    }
                })
            )
        );
    }
    doLogin() {
        if(this.checkValues(this.usernameTxt, this.passwordTxt)) {
            this.profileService.profile = this.getProfile(this.usernameTxt, this.passwordTxt);
            console.log(this.foundProfile);
        }
    }
}

现在，我的问题如下：

为什么map()内部的this.foundProfile = true;不将private foundProfile: boolean;设置为true？我敢肯定，我要以错误的方式进行操作 - 但是为什么是这样，我应该做什么？

预先感谢。

编辑：在我的loginservice中，我正在启动我的观察力：

getProfiles(): Observable<Profile[]> {
    return this.http.get<Profile[]>(this.url);
}

Answer 1

如果要更新您的undprofile，请不要将其设置为.map如果要处理此操作，则需要一个.subscribe((！

另一件事是您尝试在此诺言中承诺。

GetProfile返回仅映射的优点是您将能够更改/适应所需的每个订阅的过滤器。

// Better to put this function in profile service then call this.profileService.getProfile
getProfile(username: string, password: string) {
  return this.loginService.getProfiles()
  .map((res: any) => {
    return res.json();
  });
}
doLogin() {
  if(this.checkValues(this.usernameTxt, this.passwordTxt)) {
    // removed this.profileService.profile = this.getProfile...
      this.getProfile(this.usernameTxt, this.passwordTxt).subscribe(
        (profiles) => profiles.filter(
          profile => {
              if(profile.email == username && profile.password == password) {
                  this.profileService.profile = true; // update your service value
                  this.foundProfile = true; //Set to true so we know a profile has been found
                  return profile;
              }
          })
      )          
      console.log(this.foundProfile);
  }
}