Adding other values in toltip

[DFF-fred]

Since I'm asking questions...
My chart displays a percentage. I managed easily to add the % unit in the tooltip after the value. I was wondering how I could add the 2 values the %age is calculated from below. Something like:
Item: 20%
Buying: $80
Selling: $100

Thank you.

Fred

[LeeLenaleee]

Footer abd afterbody callback: https://www.chartjs.org/docs/master/configuration/tooltip.html#tooltip-callbacks

[DFF-fred]

Thank you for pointing out something I found before and ... scared me away ;-)

This looks way too complicated for me and I'll live without it I guess.

As a matter of fact, since I'm struggling with my items to display, I was thinking to do a one-off chart and update it each time I have new data (not keeping the past). While adding the % sign was a breathe with line charts, with polarArea since it's not longer the label being changed, but the data coming up on the tooltip, I haven't been able to achieve the same result.

Well... let's see if after a good night sleep, light comes to me. :-)

Thank you.