Script: SUM values if font is bold – Google Drive Spreadsheet

I was working on some calculations using Google Drive Spreadsheet.
Than I found out, that I would need SUM values only from cells, which has bold font… Than I found out, that there is no simple way, how to do that with basic functions included in Spreadsheet application. That was the moment, when I found out, that there is option create a custom fuction by my own needs using Google Apps Script!
Continue reading