to-csv.js

const reservedChars = /[\r\n,"]/

module.exports = function toCSV(header, rows) {
  rows = rows.map(row => row.map(valueToString).join(','))
  return [header.join(','), ...rows].join('\r\n') + '\r\n'
}

function valueToString(value) {
  return value === undefined
    ? ''
    : (typeof value === 'string' && reservedChars.test(value)) ||
      (typeof value === 'object' && value !== null)
    ? escapeString(value)
    : value
}

function escapeString(value) {
  let str = JSON.stringify(value)
  if (typeof value === 'string') {
    str = str.slice(1, -1)
  }
  str = str.replace(/"/g, '""')
  return '"' + str + '"'
}