用参数关闭JS

Question

I have an Object like this

JSON_DATA = {
    "EVENT" : "data/sequence/sequenceEvent.json",
    "CHAT" : "data/sequence/sequenceChat.json",
}

I would like to load those value so I do this

LoadJSON(JSON_DATA, function(data){
    var DATA = data;
});

function LoadJSON(jsons, callback){
    var counterLoaded = 0;
    var counterToLoad = Object.keys(jsons).length;

    var parsedData = {};
    for(var key in jsons){
        ajax.get(jsons[key], "", function(data){
            parsedData[key] = JSON.parse(data);
            counterLoaded++;
            if(counterLoaded == counterToLoad){
                callback(parsedData);
            }

        }, true)
    }
}

Now, has I know I have a closure problem, like key is always the last one.

But, I searched on the internet, and expect a setTimeOut OR a function like this

function LoadJSON(jsons, callback){
    var counterLoaded = 0;
    var counterToLoad = Object.keys(jsons).length;

    var parsedData = {};
    for(var key in jsons){
        ajax.get(jsons[key], "", (function(key){
            parsedData[key] = JSON.parse(data);
            counterLoaded++;
            if(counterLoaded == counterToLoad){
                callback(parsedData);
            }

        })(key), true)
    }
}

It would not work, but in my problem, I need to pass also the parameter data.

How can I achieve that ?

Answer 1

key is always the last one.

Option 1: using closures.

for (var key in jsons) {
  (function(k) {
    ajax.get(jsons[k], "", function(data) {
      parsedData[k] = JSON.parse(data);
      counterLoaded++;
      if (counterLoaded == counterToLoad) {
        callback(parsedData);
      }
    }, true);
  })(key);
}

Option 2: using Promise API.