Publish the Current Rate

The page also needs the selected pair’s current rate for the statistics and chart.

Create an onRateChange callback from app/page.js and call it from the converter when the computed rate changes.

useEffect(() => {
  onRateChange?.(rate);
}, [rate, onRateChange]);

Test it

Change the pair and watch the Rate statistic update.

Checkpoint

The current selected-pair rate has one source of truth and can be reused by multiple UI sections.