TypeScriptで文字列配列からCSVダウンロード

• IE対応。
• コンマや改行を含むセルは " で囲む。

declare global {
  interface Navigator {
    msSaveBlob?: (blob: any, defaultName?: string) => boolean;
  }
}

function downloadCsvBlob (data: string[][], fileName: string) {
  const bom = new Uint8Array([0xEF, 0xBB, 0xBF]);
  const re = /[,\r\n"]/;
  const csv = data.map(record => record.map(value => re.test(value)
    ? `"${value.replace(/"/g, '""')}"` : value).join(',')).join('\r\n');
  const blob = new Blob([bom, csv], { type: 'text/csv' });

  if (window.navigator.msSaveBlob) { // for IE,Edge
    window.navigator.msSaveBlob(blob, fileName);
  } else {
    const url = URL.createObjectURL(blob);
    const el = document.createElement('a');
    el.href = url;
    el.setAttribute('download', fileName);
    document.body.appendChild(el);
    el.click();
    URL.revokeObjectURL(url);
    if (el.parentNode) {
      el.parentNode.removeChild(el);
    }
  }
}