node.js - Why Aws s3 Bucket creating 0 bytes file while uploading file with creating new folder dynamically? -

i pretty new aws s3 bucket,i trying upload files different folders creation dynamically.even though script working.my s3 bucket creating 0 bytes file,and name equal folder last uploaded.

this server.js

import express 'express'; import path 'path'; import webpack 'webpack'; import webpackmiddleware 'webpack-dev-middleware' import webpackhotmidleware 'webpack-hot-middleware'; import bodyparser 'body-parser'; import aws 'aws-sdk'; import open 'open'; import uuid 'uuid'  import webpackconfig './webpack.config';   // create s3 client aws.config.loadfrompath('c.json'); var s3 = new aws.s3();  // create bucket , upload       let app = express(); app.use(bodyparser.json({limit:"50mb"})); app.use(express.static('public'));    const compiler = webpack(webpackconfig)  app.use(webpackmiddleware(compiler,{     hot:true,     publicpath:webpackconfig.output.publicpath,     noinfo:true }));  app.use(webpackhotmidleware(compiler));    app.post('/api',(req,res) => {      let imageuri = req.body.data.data_uri;     let filename = req.body.data.filename;     let filetype = req.body.data.filetype;       const name = uuid.v1();     var bucketname = 'nok-sample/'+name;       let buf = new buffer(imageuri.replace(/^data:image\/\w+;base64,/, ""),'base64');     console.log(buf.length);        s3.createbucket({bucket: bucketname}, function() {         var params = {bucket: bucketname, key: filename, body: buf,contenttype:filetype,contentlength:buf.length,acl:'public-read'};         s3.putobject(params, function(err, data) {             if (err)                 console.log(err)             else                 console.log("successfully uploaded data " + bucketname + "/" + filename);                 let resimage = {                     "awsurl":`https://s3.amazonaws.com/${bucketname}/${filename}`                 };                 res.json(resimage);                 console.log(resimage)          });     }); });    app.get('/*',(req,res) => {     res.sendfile(path.join(__dirname,'./index.html')) });   app.listen(3000,() => {     open('http://localhost:3000') });