Question

我正在订阅以下活动清单

userService.createUser(this.form).subscribe((user)=>{ this.user = user })

服务方法如下所示......

createAccount(user) {

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

        return this.http
            .post(
                '/api/accounts',
                JSON.stringify(user),
                {headers}
            )
            .map(res => res.json())
            .map((res) => {
                if (res['account']) {
                    this.authService.isLoggedIn = true;
                    this.loggedIn.next(true);
                    this.userData = res["account"];
                    return res;


                } else {

                    this.authService.isLoggedIn = false;

                }
            });

    }

我需要在createUser中以某种方式添加这样的调用，以在用户完成之前检查用户是否存在...

checkForDups(user){


        return this.http
            .get('/api/checkfordups/'+user.email)
            .map(res => res.json())
            .map((res) => {
                if (res>0) {
                    //user account exists...
                    return {'message' : 'User account exists!'};


                } else {

                    return true;

                }
            });
    }

我试过了......

createAccount(user) {

        if( this.checkForDups(user)){

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

            return this.http
                .post(
                    '/api/accounts',
                    JSON.stringify(user),
                    {headers}
                )
                .map(res => res.json())
                .map((res) => {
                    if (res['account']) {
                        this.authService.isLoggedIn = true;
                        this.loggedIn.next(true);
                        this.userData = res["account"];
                        return res;


                    } else {

                        this.authService.isLoggedIn = false;

                    }
                });
        }else{


            return {"message": "duplicate account found"};
        }

    }

但它无法正常工作。对更好的方法有任何想法吗？

Answer 1

在上一个代码中，您可以订阅checkForDups而不是在if语句中调用它。像这样：

    createAccount(user) {

        this.checkForDups(user)
        then.(result => {

            if( this.checkForDups(user)){

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

                return this.http
                    .post(
                        '/api/accounts',
                        JSON.stringify(user),
                        {headers}
                    )
                    .map(res => res.json())
                    .map((res) => {
                        if (res['account']) {
                            this.authService.isLoggedIn = true;
                            this.loggedIn.next(true);
                            this.userData = res["account"];
                            return res;


                        } else {

                            this.authService.isLoggedIn = false;

                        }
                    });
            }else{


                return {"message": "duplicate account found"};
            }

        });

    }

在checkForDups中，不要忘记在http调用后调用.toPromise()：

    import 'rxjs/add/operator/toPromise'; // import the .toPromisse method here
    ...
    checkForDups(user){


        return this.http
            .get('/api/checkfordups/'+user.email)
            .map(res => res.json())
            .map((res) => {
                if (res>0) {
                    //user account exists...
                    return {'message' : 'User account exists!'};


                } else {

                    return true;

                }
            })
            .toPromise(); // do not forget this so you would not be able to call the `.then(...)` method inside createAccount
    }

Angular 2在创建帐户之前检查帐户

1 个答案: