Question

我已经尝试了所有可以找到的方法，建议将promise对象返回到resolve，以便我的函数将异步处理，但仍然无法返回正确的数据 - 请告知：

        .state("app.deals.private", {
            url: "/private/",
            resolve: {
                dealsFeatured: function(Deals, $rootScope) {
                    return Deals.getDeals('FEATURED', function(data) {
                        // console.log('deals featured', data); // DATA IS HERE
                        $rootScope.loading = false;
                        return data; 
                    });
                },
                dealsGeneral: function(Deals, $rootScope, dealsFeatured) {
                    return Deals.getDeals('GENERAL', function(data) {
                        // console.log('deals general', data);  // DATA IS HERE
                        $rootScope.loading = false;
                        return data; 
                    });
                },
                dealsCats: function(Deals, dealsFeatured, dealsGeneral, $q) {

                    // ALL DEPENDENCIES HAVE DATA HERE 

                    // build a promise object
                    var deferred = $q.defer();

                    Deals.mergeCats(dealsFeatured, dealsGeneral, $q, function(data){
                        console.log("received dealsCats: " + data); 
                        //BUT....NOTHING IS RETURNED HERE, WHY NOT?!?!?!?

                        deferred.resolve(data);
                    });

                    //return the promise object
                    return deferred.promise;

                },

这是我服务中的代码（注意数据是正确的，并在回调之前输出到控制台：

 api.service('Deals', function(){

    this.mergeCats = function(dealsFeatured, dealsGeneral, $q, callback){

    // make one big array
    var allCats = [];
    if(Array.isArray(dealsFeatured.data.discountTermsWithCounters.cats)){
        allCats = dealsFeatured.data.discountTermsWithCounters.cats;
    }
    if(Array.isArray(dealsGeneral.data.discountTermsWithCounters.cats)){
        allCats = allCats.concat(dealsGeneral.data.discountTermsWithCounters.cats);
    }

    // now recreate the array into something we can work with
    var newCats = [];
    angular.forEach(allCats, function(value, key){
        if(newCats[value.title]){
            newCats[value.title].count += value.count;
        } else {
            newCats[value.title] = value;
        }
    });
    // after all is completed, return data to the promise object
    $q.all(allCats).then(function () {
        console.log('newCats',newCats);  // CORRECT DATA IS OUTPUTTED HERE
            // newCats data looks like this in console:
            // Array: [Herbs & Homeopathic: Object, Frozen: Object, Groceries: Object, Body Care: Object, General Merchandise: Object…]
        callback(newCats);
    });

};
});

请告知，我错过了什么？

Answer 1

您对dealsCats和Deals.mergeCats感到困惑，以及如何以及为何使用$q作为参数传递。

mergeCats会$q.all返回一个承诺，但mergeCats只执行同步操作。不需要$q，承诺或回调：

因此，请将Deals.mergeCats更改为以下内容：

this.mergeCats = function(dealsFeatured, dealsGeneral){
  // some other code here that creates allCats
  return allCats;
}

出于同样的原因，您$q.defer不需要dealsCats：

resolve: {
    //...,
    dealsCats: function(Deals, dealsFeatured, dealsGeneral){
       return Deals.mergeCats(dealsFeatured, dealsGeneral);
    }
}

将数据从简单函数返回到UI路由器的问题解决了

1 个答案: