Question

我想念一些事情，完全掌握承诺的概念。

我尝试实现这一点：一旦我的http返回就调用一个函数，如下所示

onSubmit(event: any) {
        this.submitted  = true;
        event.preventDefault();

        this.si
        .signIn(this.emailAddress, this.password, this.keepSignedIn)
        .toPromise()
        .next((res:any) => {
            this.router.navigate(['dashboard']);
        });
}

但得到了错误：

this.si
.signIn(this.emailAddress, this.password, this.keepSignedIn)
.toPromise is not a function.':

在服务中，我按如下方式写了我的电话;

signIn(emailAddress: string, password: string, keepSignedIn: boolean): Promise<any> {
    console.log("SigninService, emailaddress="+emailAddress);
    console.log("SigninService, password="+password);

    const auth = this.buildAuthToken(emailAddress, password, keepSignedIn);
    const headers = this.getHeaders();

    console.log("SigninService, headers="+JSON.stringify(headers));

    const url = 'http://dev-user.zeens.ws/api/v1/me';
    return this.http.get(url, {headers: headers})
    .toPromise()
    .then(response => {
        console.log("response="+JSON.stringify(response.json()));
        this.user = response.json().result;

        console.log("response="+JSON.stringify(this.user));

        localStorage.setItem('user', JSON.stringify(this.user));

        return this.user;
        /*
        console.log("signin="+JSON.stringify(response.json().data));
        return response.json().data;
        */
    })
    .catch(this.handleError);
}

Answer 1

return this.http.get(url, {headers: headers})
.toPromise()
.then(response => {
  ...
})
.catch(this.handleError);

在您的服务中，您已使用toPromise。在您编写时，您的函数具有以下定义：

signIn(emailAddress: string, password: string, keepSignedIn: boolean): Promise<any>

然后你做：

this.si
    .signIn(this.emailAddress, this.password, this.keepSignedIn)
    .toPromise() // <---- PROBLEM
    .next((res:any) => {
        this.router.navigate(['dashboard']);
    });

您可以尝试在承诺上应用toPromise。

很奇怪，你为什么要把它转换为诺言？

你可以这样做：

signIn(emailAddress: string, password: string, keepSignedIn: boolean): Observable<any> {
    ...

    return this.http.get(url, {headers: headers})
    .map((response: Response) => {
        this.user = response.json().result;

        localStorage.setItem('user', this.user);

        return this.user;
    })
    .catch(this.handleError);
}

onSubmit(event: any) {
    this.submitted  = true;

    this.si
        .signIn(this.emailAddress, this.password, this.keepSignedIn)
        .subscribe((res:any) => {
            this.router.navigate(['dashboard']);
        });

    // returning false is equivalent to event.preventDefault()
    return false;
}

编辑：
为了定义地图，您需要导入它在main.ts或仅加载一次的地方，添加以下内容：

import 'rxjs/add/operator/map';

例如，这是我的导入：

// rxjs operators
// see node_module/rxjs/Rxjs.js
// statics
import 'rxjs/add/observable/throw';
// operators
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/delay';
import 'rxjs/add/operator/debounceTime';
import 'rxjs/add/operator/distinctUntilChanged';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/let';
import 'rxjs/add/operator/switchMap';
import 'rxjs/add/operator/toPromise';
import 'rxjs/add/operator/withLatestFrom';
import 'rxjs/add/operator/combineLatest';

// observables
import 'rxjs/add/observable/empty';

尝试在Angular2中链接承诺时出现问题

1 个答案: