thousand separator in number($m,$b) in tooltip

Hello Expert, Mouse-over (tooltip) : I have running application where i plot bar chart  (x -string & y -decimal). We would like to add thousand separator  Like 6, 234,718 on mouse over .  I have tried using parseDecimal() and formatDecimal() . For example Current Mouseover (Tooltip) – $6234718. Looking for                              – $6, 234,718. I have also tried with hovertemplate, hoverinfo, hovertext  kind of JSON tags.  Thanks, Amol Salunke