Count colored cells in Google sheets - create custom formula

In the google sheets, use the following script and enjoy the function to count the colored cells 

=countColoredCells(B59:AF59, "#274e13")  #Green color code

 function countColoredCells(countRange,colorRef) {

  var count = 0;

  var activeRange = SpreadsheetApp.getActiveRange();

  var activeSheet = activeRange.getSheet();

  var formula = activeRange.getFormula();

 

  var rangeA1Notation = formula.match(/\((.*)\,/).pop();

  var range = activeSheet.getRange(rangeA1Notation);

  var bg = range.getBackgrounds();

  var values = range.getValues();

   

  for(var i=0;i<bg.length;i++)

    for(var j=0;j<bg[0].length;j++)

    {

      if( bg[i][j] == colorRef )

        count=count+1;

    }  

  return count;

};