如何正确构建异步程序以确保正确的结果

我有一个nodejs程序，它请求一系列XML文件，解析它们，然后将输出放在一个数组中，该数组作为CSV文件写入磁盘。

该程序大部分工作，但偶尔文件在数组中的顺序错误

我希望结果的顺序与URL的顺序相同。URL 存储在数组中，因此当我获取 XML 文件时，我会检查源数组中 URL 的索引，并将结果插入目标 URL 中的同一索引处。

谁能看到允许结果以错误顺序结束的缺陷？

addResult = function (url, value, timestamp) {
        data[config.sources.indexOf(url)] = {
            value : value,
            timestamp : timestamp,
            url : url
        };
        numResults++;
        if (numResults === config.sources.length) { //once all results are in build the output file
            createOutputData();
        }
    }
fs.readFile("config.json", function (fileError, data) {
    var eachSource, processResponse = function (responseError, response, body) {
        if (responseError) {
            console.log(responseError);
        } else {
            parseXML(body, {
                explicitArray : false
            }, function (xmlError, result) {
                if (xmlError) {
                    console.log(xmlError);
                }
                addResult(response.request.uri.href, result.Hilltop.Measurement.Data.E.I1, moment(result.Hilltop.Measurement.Data.E.T));
            });
        }
    };
    if (fileError) {
        console.log(fileError);
    } else {
        config = JSON.parse(data); //read in config file
        for (eachSource = 0; eachSource < config.sources.length; eachSource++) {
            config.sources[eachSource] = config.sources[eachSource].replace(/ /g, "%20"); //replace all %20 with " " 
            request(config.sources[eachSource], processResponse); //request each source
        }
    }
});
var writeOutputData, createOutputData, numResults = 0, data = [], eachDataPoint, multipliedFlow = 0;
writeOutputData = function (output, attempts) {
    csv.writeToPath(config.outputFile, [ output ], {
        headers : false
    }).on("finish", function () {
        console.log("successfully wrote data to: ", config.outputFile);
    }).on("error", function (err) { //on write error
        console.log(err);
        if (attempts < 2) { //if there has been less than 3 attempts try writing again after 500ms
            setTimeout(function () {
                writeOutputData(output, attempts + 1);
            }, 500);
        }
    });
};
createOutputData = function () {
    var csvTimestamp, output = [];
    if (config.hasOwnProperty("timestampFromSource")) {
        csvTimestamp = data.filter(function (a) {
            return a.url === config.sources[config.timestampFromSource];
        })[0].timestamp.format("HHmm");
        console.log("timestamp from source [" + config.timestampFromSource + "]:", csvTimestamp);
    } else {
        csvTimestamp = data.sort(function (a, b) { //sort results from oldest to newest
            return a.timestamp.unix() - b.timestamp.unix();
        });
        csvTimestamp = csvTimestamp[0].timestamp.format("HHmm");//use the oldest date for the timestamp
        console.log("timestamp from oldest source:", csvTimestamp);
    }
    //build array to represent data to be written
    output.push(config.plDestVar); //pl var head address first
    output.push(config.sources.length + 1); //number if vars to import
    output.push(csvTimestamp); //the date of the data 
    for (eachDataPoint = 0; eachDataPoint < data.length; eachDataPoint++) { //add each data point
        if (config.flowMultiplier) {
            multipliedFlow = Math.round(data[eachDataPoint].value * config.flowMultiplier); //round to 1dp and remove decimal by *10
        } else {
            multipliedFlow = Math.round(data[eachDataPoint].value * 10); //round to 1dp and remove decimal by *10
        }
        if (multipliedFlow > 32766) {
            multipliedFlow = 32766;
        } else if (multipliedFlow < 0) {
            multipliedFlow = 0;
        }
        output.push(multipliedFlow);
    }
    console.log(output);
    writeOutputData(output, 0); //write the results, 0 is signalling first attempt
};