javascript - AngularJS 服务不返回 promise

Question

我最近开始使用 AngularJS，虽然我可以看到一些改进，但我无法理解这些 promise 。我创建了一个登录服务，它使用 Parse 框架使用户能够注册，并创建了一个注册 Controller ，将数据从表单发送到服务。由于注册需要几秒钟，我决定使用 promise 在当前用户注册后将其返回到登录 Controller 。不幸的是，我不断收到此错误:无法读取未定义的属性“then”。有人可以指出我正确的方向吗？

Controller :

(function () {
'use strict';

angular
    .module('app.register')
    .controller('RegisterController', RegisterController);

RegisterController.$inject = ['$q', 'logger', 'loginservice'];
/* @ngInject */
function RegisterController($q, logger, loginservice) {
    var vm = this;
    vm.title = 'Register'; 
    vm.register = register;     
    vm.user = {
        username: "",
        password: "",
        email: ""
    };

    activate();

    function activate() {
        logger.info('Activated Register View');
    }

    function register() {
        var promise = loginservice.register(vm.user.username, vm.user.email, vm.user.password);

        promise.then(function(userData) {
            console.log("User: ", userData);
        });
    }
}
})();

服务:

(function() {
'use strict';

angular
    .module('app.core')
    .factory('loginservice', loginservice);

loginservice.$inject = ['$http', '$q', 'logger'];
/* @ngInject */
function loginservice($http, $q, logger) {
    var service = {
        // logIn: logIn,
        // logOut: logOut,
        register: register
    };

    return service;

    function initialize() {
        console.log("parse initialized");
    }

    function register(username, email, password) {
        //alert("HELLO FROM " + username + " " + password + " " + email);

        Parse.initialize(appId, parseId);
        var user = new Parse.User();
        user.set("username", username);
        user.set("password", password);
        user.set("email", email);

        $http.get(user.signUp(null, {
         success: function(user) {
            return user;
          },
          error: function(user, error) {
            return error.message;
            // Show the error message somewhere and let the user try again.
            alert("Error: " + error.code + " " + error.message);
          }
        })).then(function() {
            return user;
        });
    }
}
})();

Answer 1

您只需返回 $http 调用:

function register(username, email, password) {
        //alert("HELLO FROM " + username + " " + password + " " + email);

        Parse.initialize(appId, parseId);
        var user = new Parse.User();
        user.set("username", username);
        user.set("password", password);
        user.set("email", email);

        return $http.get(user.signUp(null, {
         success: function(user) {
            return user;
          },
          error: function(user, error) {
            return error.message;
            // Show the error message somewhere and let the user try again.
            alert("Error: " + error.code + " " + error.message);
          }
        })).then(function() {
            return user;
        });
    }

如果您不返回在 $http 调用期间创建的 Promise，则函数(默认情况下)将返回 undefined。