I'm trying to upload my file in custom folder path(uploadsFolder/) rather than default CloudBackEnd's upload folder. Below code is not working.

Please guide me on how to achieve this

My Folder Structure
/
CloudBackEnd
uploadsFolder

My Code
var request = require('request');
var cloudbackend = require('appdrag-cloudbackend');
var appID = process.env.APPID; // Read from environment variables
var APIKey = process.env.APIKEY; // Read from environment variables
cloudbackend.init(APIKey, appID);
exports.handler = (event, context, callback) => {

var postedFiles = event["FILES"];

if(postedFiles.length>0){
    for(i=0;i<postedFiles.length;i++){
        var tmpPath = postedFiles[i]["path"]; 
        var destPath = "uploadsFolder/"+ tmpPath;
        cloudbackend.fileSaveUploaded(tmpPath,destPath).then(callback(null, destPath));
    } // end -for
}
else {
    callback(null, postedFiles.length);
}

}; // end - handler