Say the currency once, and stop hedging about old prices.

The balance read "US$74.67 USD" — the symbol and the unit tag saying the same
thing twice. Amounts now format bare, like sats and BTC do: whatever labels
the number says which money it is. The currency symbol stays where a number
stands alone in prose, which is the "Worth then" line and nowhere else.

The '~' marking a payment older than any price we sampled is gone too. It was
bookkeeping the beta doesn't need: a payment we have a price for is shown at
that price, one we don't is shown at today's, and nobody has to learn a
squiggle.

The currency picker has moved to sit beside the language picker at the foot
of the page — display preferences together, where they're findable. It spent
one day under Settings → Network, where it wasn't.

And a bug this feature exposed rather than caused: nine notices end in the
word "sats" in every language we ship, and were being handed the display
unit. "Uncooperative exit costs about US$2.03 sats" — and long before fiat,
"about 0.00435397 sats" for anyone in BTC. They're given sats now, which is
what they claim to be showing.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_019mrt228Upn9nNCwGixzSLx

1 files changed, 14 insertions, 3 deletions

diff --git a/src/rates.js b/src/rates.js
index bc32bd7..19b3512 100644
--- a/src/rates.js
+++ b/src/rates.js
@@ -116,13 +116,24 @@ export async function refreshRates({ force = false } = {}) {
 // it does — a third position that shows blanks is worse than two that work.
 export const haveRate = () => rateNow() != null;
 
+// Two shapes. `fmtFiat` carries its own currency symbol, for a line of prose
+// that has to say what the number is. `fmtFiatBare` is just the number, for
+// the places where the unit is already spelled out beside it — a balance
+// under its USD tag reading "US$74.67 USD" says it twice.
 export function fmtFiat(sats, rate, code = getCurrency()) {
   if (!rate) return '';
   const v = (Number(sats) / 100_000_000) * rate;
-  const digits = Math.abs(v) < 1 && v !== 0 ? 4 : 2;
   try {
-    return v.toLocaleString(undefined, { style: 'currency', currency: code, maximumFractionDigits: digits, minimumFractionDigits: 2 });
+    return v.toLocaleString(undefined, { style: 'currency', currency: code, maximumFractionDigits: fiatDigits(v), minimumFractionDigits: 2 });
   } catch {
-    return v.toFixed(digits) + ' ' + code; // a code Intl doesn't know
+    return fmtFiatBare(sats, rate) + ' ' + code; // a code Intl doesn't know
   }
 }
+export function fmtFiatBare(sats, rate) {
+  if (!rate) return '';
+  const v = (Number(sats) / 100_000_000) * rate;
+  return v.toLocaleString(undefined, { maximumFractionDigits: fiatDigits(v), minimumFractionDigits: 2 });
+}
+// Under a unit of currency, sats are small: a tenth of a cent still deserves
+// to be a number rather than 0.00.
+const fiatDigits = (v) => (Math.abs(v) < 1 && v !== 0 ? 4 : 2);