NodeJS-循环内的嵌套异步函数

Question

我正在尝试在异步函数中获取一个异步函数，以返回创建和返回对象列表所需的数据。但是我似乎无法获得其余代码来等待异步功能完成。我尝试使用Promise，但它仍然没有等待异步功能。

我希望代码在'followed'子句中等待内部getUser函数。

这是代码。

            var count = 0;
            var activities = [];

            var getUsers = function(activity, callback){

                var text_arr = activity.text.split("/");

                get_user(res, text_arr[0], text_arr[0], function (user) {

                    if(user != null){

                        if (text_arr[2] == "created"){

                            activity = {
                                "id":activity.id,
                                "user_id":text_arr[0],
                                "user_name": user.user.name,
                                "event_name": text_arr[3],
                                "event_id": text_arr[4],
                                "event_img":(text_arr[5]) ? text_arr[5].split("$").join("/") : null,
                                "type": "CREATED_EVENT",
                                "date": activity.modified_ts
                            }
                        }

                        if (text_arr[2] == "commented"){

                            activity = {
                                "id":activity.id,
                                "user_id":text_arr[0],
                                "user_name": user.user.name,
                                "event_name": text_arr[3],
                                "event_id":text_arr[4],
                                "event_img": (text_arr[6]) ? text_arr[6].split("$").join("/") : null,
                                "comment": text_arr[5],
                                "type": "COMMENTED_EVENT",
                                "date": activity.created_ts
                            }
                        }

                        if (text_arr[2] == "followed"){

                            function f_promise() {
                              return new Promise(function (resolve, reject) {
                                get_user(res, text_arr[3], text_arr[3], function (following) {
                                    resolve(following);
                                });
                              })
                            }

                            f_promise().then(following => {
                                activity = {
                                    "id":activity.id,
                                    "user_id":text_arr[0],
                                    "user_name": user.user.name,
                                    "followed_id": text_arr[3],
                                    "followed_name": following.name,
                                    "followed_img": (text_arr[5]) ? String(text_arr[6]).split("$").join("/") : null,
                                    "type": "FOLLOWED_USER",
                                    "date": activity.modified_ts
                                }
                            })
                        }

                        if (text_arr[2] == "liked"){

                            activity = {
                                "id":activity.id,
                                "user_id":text_arr[0],
                                "user_name": user.user.name,
                                "event_name": text_arr[3],
                                "event_id": text_arr[4],
                                "event_img": (text_arr[5]) ? text_arr[5].split("$").join("/") : null,
                                "type": "LIKED_EVENT",
                                "date": activity.modified_ts
                            }
                        }

                        if (text_arr[2] == "attending"){

                            activity = {
                                "id":activity.id,
                                "user_id":text_arr[0],
                                "user_name": user.user.name,
                                "event_name": text_arr[3],
                                "event_id": text_arr[4],
                                "name": text_arr[3],
                                "event_img":(text_arr[5]) ? text_arr[5].split("$").join("/") : null,
                                "type": "ATTENDED_EVENT",
                                "date": activity.modified_ts
                            }
                        }

                        activities.push(activity)
                    }

                    count++;

                    if(result.length == count){
                        callback(activities)    
                    }
                });
            }

            //start here
            if(JSON.stringify(result) == "[]"){
                var data = {"activities": []};
                callback(data);
            }else{
                async.forEach(result, getUsers, function(activities) {

                    var data = {"activities":activities};

                    callback(data);
                })
            }