var AWS = require('aws-sdk');
AWS.config.update({accessKeyId: 'mykey', secretAccessKey: 'mysecret', region: 'myregion'});
var s3 = new AWS.S3();

var params = { 
 Bucket: 'mystore.in',
 Delimiter: '/',
 Prefix: 's/5469b2f5b4292d22522e84e0/ms.files/'
}

s3.listObjects(params, function (err, data) {
 if(err)throw err;
 console.log(data);
});