add BOM in CSV output if encoding is UTF-8

[stevencjhsiao]

When open output UTF-8 CSV file by excel, if the UTF-8 CSV is lack of BOM header , Excel will identify CSV as ISO-8858-1 encoding. The Chinese character inside the Excel will unreadable.

function toCSV($delm="\t", $add_title=true, $encoding=null)
{
    $out = '';
    // add BOM if UTF-8
    if ($encoding == 'UTF-8')
        $out = chr(239) . chr(187) . chr(191);

[thomascube]

From my experience, BOMs usually cause more problems than they solve but in this case, it might make sense. Could you possibly check if the CSV (with BOM) also works when imported in Outlook? That's another very important use-case.

[stevencjhsiao]

CSV with BOM still can be imported to outlook in my test. The only defect is the first field name will include BOM, but it will not effect the data in first column.

However, there are still additional two issue when importing Traditional Chinese CSV to outlook.

1. CSV must use Big5 encoding
2. the EOL character must be CR+LF

You may consider to add option for BOM and EOL in UI.

[thomascube]

The only defect is the first field name will include BOM

This may be a problem with automatic field assignments in Outlook or other applications

You may consider to add option for BOM and EOL in UI

Unfortunately another setting non-tech-savvy users will not understand.