Save excel friendly csv for Mac/Windows

saveCsvAsFile.js

// Save excel friendly csv for Mac/Windows.
// See also
// http://qiita.com/bump_of_kiharu/items/f41beec668e1f3ea675e#%E5%8F%82%E8%80%83
// https://stackoverflow.com/questions/17879198/adding-utf-8-bom-to-string-blob

const UTF16BOM = '\ufeff';

const isIE = false || !!document.documentMode;
const isEdge = navigator && /Edge\/\d./i.test(navigator.userAgent);

// https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/DataView#Endianness
const isLittleEndian = (() => {
  let buffer = new ArrayBuffer(2);
  new DataView(buffer).setInt16(0, 256, true /* littleEndian */);
  return new Int16Array(buffer)[0] === 256;
})();

function saveCsvAsFile(text, filename) {

  let contents;
  const csvString = UTF16BOM + text; //UTF-16
  if (isLittleEndian()) {
    let array = [];
    for (let i = 0; i < csvString.length; i++){
      array.push(csvString.charCodeAt(i));
    }
    contents = new Uint16Array(array);
  } else {
    let buf = new ArrayBuffer(csvString.length * 2);
    let view = new DataView(buf);
    for (let i = 0, j = 0; i < csvString.length; i++, j = i * 2) {
      view.setUint16( j, csvString.charCodeAt(i), true );
    }
    contents = buf;
  }
  const file = new Blob([contents], {type: 'text/csv;charset=utf-16le;'});

  if (isIE || isEdge) {
    navigator.msSaveBlob(file, filename);
  } else {
    const url = window.URL.createObjectURL(file);
    const body = document.body;
    const a = document.createElement('a');

    body.appendChild(a);
    a.setAttribute('download', filename);
    a.setAttribute('href', url);
    a.style.display = 'none';
    a.click();
    a.parentNode.removeChild(a);
    setTimeout(function() {
      window.URL.revokeObjectURL(url);
    }, 10);
  }
}