In one of my Next/React App pages, I render a scrollable chart as seen below

I want to be able to fire a function only when the user has scrolled to the very bottom of the chart.

I know window.scrollY will be based on the outer scrollbar, not the inner one in the chart.

How can I measure the window.scrollY value of the inner chart?

Or is there a better way to know when the user has reached the bottom of the chart instead of using the window Y value?