javascript - How to read and write data from csv using fast csv -

i reading data csv , transforming data. want write data new csv file getting created data not getting populated.

here have tried

const fs = require('fs'); var csv = require("fast-csv");  var stream = fs.createreadstream("/home/rahul/downloads/it.csv"); var ws = fs.createwritestream("/home/rahul/downloads/my.csv");  csv  .fromstream(stream)  .transform(function(data){     return data.map(function(ip) {         return number(             ip.split(".")               .map(d => ("000"+d).substr(-3) )               .join("")           );        })   })  .on("data", function(data){      console.log(data); // logs [ 5009000000, 5009255255 ]  })  .on("end", function(data){     csv.write(data).pipe(ws);   });