返回循环内调用的回调结果串联 [英] Return the concatenation of callbacks result called within a loop

问题描述

我的数据在MongoDB中。我试图在启动时更新分数。
但是，我需要根据循环进行多次查询。

My data is in MongoDB. I am trying to update the score when initiated. However, I need to make several queries depending upon loop.

最后我想获得所有回调的连接结果，然后调用a具有此连接结果的函数。

At the end I would like to get the concatenated results of all the callbacks and then call a function with this concatenation result.

function getCurrentScore() {
    var teamScores = "";
    (function(){
        for(var i=0 ; i< teams.length; i++) {
        (function(i){
            PingVoteModel.count({"votedTo": "TEAM"+(i+1)}, function( err, count)
                {
              teamScores += "<Team" + (i+1) + "> " + count + "\t";
            });
            }(i));
        }
    }());
    return teamScores;
}

如何获得串联的teamScore？

How can I get concatenated teamScore ?

推荐答案

跟踪你还在等待多少结果，然后在完成后调用回调：

Keep track of how many results you're still waiting for and then call a callback when done:

function getCurrentScore(callback) {
    var teamScores = "", teamsLeft = teams.length;
    for(var i=0 ; i<teams.length; i++) {
        (function(i){
            PingVoteModel.count({"votedTo": "TEAM"+(i+1)}, function( err, count) {
                teamScores += "<Team" + (i+1) + "> " + count + "\t";
                if (--teamsLeft === 0) {
                    callback(teamScores);
                }
            });
        }(i));
    }
}

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