simple parse to sha1

csvParseToSha1.js

var fs = require('fs');
var csv = require("fast-csv");
var sha1 = require('sha1');

var inputFile = 'emailList.csv';
var outputFile = 'sha1List.csv';

var csvStream = csv.format({headers: false}),
    writableStream = fs.createWriteStream(outputFile);

csvStream.pipe(writableStream);

csv
 .fromPath(inputFile)
 .on("data", function(data){
   var hashed = sha1(data[0])
   csvStream.write([hashed]);
 })
 .on("end", function(){
     csvStream.end();
     console.log("done");
 });