js download array as csv

download-csv.js

// https://jsfiddle.net/3an24jmw/25/

asUtf16 = (str) ->
  buffer = new ArrayBuffer(str.length * 2)
  bufferView = new Uint16Array(buffer)
  bufferView[0] = 0xfeff
  for i in [0..str.length]
    val = str.charCodeAt(i)
    bufferView[i + 1] = val
  bufferView


makeExcelCsvBlob = (rows) ->  
  new Blob([asUtf16(toTsv(rows)).buffer], {type: "text/csv;charset=UTF-16"})


toTsv = (rows) ->
  escapeValue = (val) ->
    if typeof val is 'string'
      '"' + val.replace(/"/g, '""') + '"'
    else if val?
      val
    else
      ''
  rows.map((row) -> row.map(escapeValue).join('\t')).join('\n') + '\n'


downloadExcelCsv = (rows, attachmentFilename) ->
  blob = makeExcelCsvBlob(rows)  
  a = document.createElement('a')
  a.style.display = 'none'
  a.download = attachmentFilename
  document.body.appendChild(a)
  a.href = URL.createObjectURL(blob)
  a.click()
  URL.revokeObjectURL(a.href)
  a.remove()
  return


# Example:
rows = [
  ['id', 'name', 'age']
  [1, 'John Doe', 43]
  [2, 'Jane Doe', 42]
  [3, 'Foo', 3]
]

window.exampleDownload = -> 
  downloadExcelCsv(rows, 'exported-data.csv')