const { Readable } = require('stream')
const { Parser } = require('csv-parse')

async function parse (bom, content, record_delimiter) {
  const input = Readable.from(Buffer.concat([bom, content]))
  const parser = new Parser({ bom: true, record_delimiter })

  input.pipe(parser)

  for await (const line of parser) {
    console.log(line)
  }
}

async function main () {
  const lines = ['a,b,c', '1,2,3'].join('\r\n')

  console.log('utf8')
  await parse(Buffer.from([0xef,0xbb,0xbf]), Buffer.from(lines, 'utf8'))

  console.log('utf16le')
  await parse(Buffer.from([0xff, 0xfe]), Buffer.from(lines, 'utf16le'))

  console.log('utf16le \\r\\n')
  await parse(Buffer.from([0xff, 0xfe]), Buffer.from(lines, 'utf16le'), ['\r\n'])
}

main()

/* output:

utf8
[ 'a', 'b', 'c' ]
[ '1', '2', '3' ]
utf16le
[ 'a', 'b', 'c' ]
[ '\n1', '2', '3' ]
utf16le \r\n
[ 'a', 'b', 'c' ]
[ '1', '2', '3' ]

*/