remove bom from tsv output

Author: ddooley

lib/utils/files.js

@@ -154,6 +154,9 @@ function writeWorkbook(workbook, baseName, ext, opt = {}) {
  * and https://github.com/SheetJS/sheetjs
  * Solution at bottom of: https://github.com/SheetJS/sheetjs/issues/943
  * The "Comma Separated Values" format is actually UTF-8 with BOM prefix.
+ * A “U+” designation refers to a character, and in this case that would be
+ * U+FEFF; the start of the file is the three-byte sequence EF BB BF which is
+ * how U+FEFF is represented in UTF-8.
  * @param {Workbook} workbook workboox to download.
  * @param {String} baseName Basename of downloaded file.
  * @param {String} ext Extension of downloaded file.
@@ -224,8 +227,8 @@ export function exportWorkbook(workbook, baseName, ext) {
        * available, and resulting file is UTF-8 +BOM anyways.
       */
       case 'tsv': // UTF-8 BOM version
-        // SheetJS note: For compatibility with Excel, csv output will always
-        // include the UTF-8 byte order mark ("BOM").
+        // SheetJS note: For compatibility with Excel, writeFile() csv output 
+        // will always include the UTF-8 byte order mark ("BOM").
         //writeFile(workbook, fileName, {bookType: 'csv', FS: '\t'}); 
         data = XlsxUtils.sheet_to_csv(worksheet, {FS: '\t'});
         //data = '\uFEFF' + data; //BOM