Angular: 延迟变量在 then-method 中未定义

Question

在我的 Angular.JS 代码中，我用 GET/JSONP 调用 Yahoo YQL API，我确实得到了响应。但是有两个问题。

它调用错误方法而不是成功方法。为什么？
延迟变量似乎在错误函数中未定义。为什么？

您可以找到 JsFiddle here. It is based on an AJAX example.

function DefaultCtrl($log, $scope, $http, myService) {

    var promise = myService.getSuggestions('yahoo');

    promise.then(
          function(payload) { 
              $log.info('receiving data', payload);
              $scope.test = payload;
              $log.info('received data', payload);
          },
          function(errorPayload) {
              $log.error('failure loading suggestions', errorPayload);
          });    
}

angular.module('MyModule', [])
.factory('myService', function ($http, $log, $q) {
    return {
        getSuggestions: function (symbol) {            

            var deferred = $q.defer();

            $http.jsonp("http://d.yimg.com/autoc.finance.yahoo.com/autoc", {
                cache: true,
                params: { 
                    callback: "YAHOO.Finance.SymbolSuggest.ssCallback",               
                    query: symbol
                }
            })
            .success(function(data) {
                deferred.resolve(data);
            })
            .error(function(msg, code) {
                $log.error("error");
                deferred.reject(msg);  // <---- error occurs here!
                $log.error(msg, code);
            });

            var YAHOO = window.YAHOO = {Finance: {SymbolSuggest: {}}};
            YAHOO.Finance.SymbolSuggest.ssCallback = function (data) {
                $log.info("received data", data);
            }; // YAHOO.Finance     

            return deferred.promise;
        }
    }
});

Answer 1

这是一个有效的 example。您必须在承诺回调中传递回调函数，然后让您的回调拒绝或解决承诺。我认为您发布的代码的问题在于，在执行回调后 success 和 error 都被执行，结果未定义的 var 是 resolved/rejected.

var myApp = angular.module('MyModule', []);

myApp.controller('DefaultCtrl', function ($log, $scope, $http, myService) {

    var promise = myService.getSuggestions('yahoo');

    promise.then(

    function (payload) {
        $log.info('receiving data in DefaultCtrl', payload);
        $scope.test = payload;
    },

    function (errorPayload) {
        $log.error('failure loading suggestions', errorPayload);
    });

});


myApp.factory('myService', function ($http, $log, $q) {
    return {
        getSuggestions: function (symbol) {

            var YAHOO = window.YAHOO = {
                Finance: {
                    SymbolSuggest: {}
                }
            };
            YAHOO.Finance.SymbolSuggest.ssCallback = function (data) {
                $log.info("received data in ssCallback", data);
                deferred.resolve(data);
            }; // YAHOO.Finance     

            var deferred = $q.defer();

            $http.jsonp("http://d.yimg.com/autoc.finance.yahoo.com/autoc", {
                cache: true,
                params: { 
                    callback: "YAHOO.Finance.SymbolSuggest.ssCallback",               
                    query: symbol
                }
            })
            .then(YAHOO.Finance.SymbolSuggest.ssCallback);

            return deferred.promise;
        }
    }
});

Angular: 延迟变量在 then-method 中未定义

Angular: deferred var is undefined in then-method

jquery

angularjs

jsonp

jquery-deferred

q