node.js Stream

var fs=require('fs')var readStream=fs.createReadStream('11.mp4')var writeStream=fs.createWriteStream('22.mp4')readStream.on('data',function(chunk){if(writeStream.write(chunk)===false){readStream.pause()}})writeStream.on('drain',function(){readStream.resume()})readStream.on('end',function(){writeStream.end()})