Nodejs Express wants to send Buffer with BOM in Response

This may be a client-side issue to retrieve.

I accessed the browser using the following code. The BOM was left in the files downloaded by Chrome in OS X and IE11 in Win.
node —v10.6.0(OSX)
express:4.17.1

I corrected the questionnaire, but there was an unnecessary semicolon at the end of the Buffer line.If it still exists in the actual code, it may be a different problem, so I will let you know just in case.

var express=require('express')
var app=express()

app.get('/', function(req,res){
    res.contentType('text/csv');
    res.attachment('response.csv');
    res.write(
        Buffer.concat ([Buffer.from([0xef, 0xbb, 0xbf], Buffer.from('csv, string, here')])
    );
    res.end();
})
app.listen(3000,()=>console.log('3000'))

The image is an IE downloaded file opened in a binary editor.