1 files changed, 56 insertions, 0 deletions
diff --git a/src/format.js b/src/format.js
new file mode 100644
index 0000000..6191033
--- /dev/null
+++ b/src/format.js
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+// Small formatting helpers. Internally amounts are integer satoshis (Number;
+// safe because max BTC supply ~2.1e15 sats < Number.MAX_SAFE_INTEGER).
+
+export const SATS = 100_000_000;
+
+export function btc(sats) {
+  return (Number(sats) / SATS).toFixed(8);
+}
+
+// "0.01234500" with the trailing-zero portion dimmed is done in CSS; here we
+// just produce a clean fixed-8 string.
+export function fmtBtc(sats) {
+  return btc(sats);
+}
+
+export function fmtSats(sats) {
+  return Number(sats).toLocaleString('en-US');
+}
+
+export function fmtUsd(sats, price) {
+  if (!price) return '';
+  const usd = (Number(sats) / SATS) * price;
+  return usd.toLocaleString('en-US', { style: 'currency', currency: 'USD' });
+}
+
+// Parse a user-entered amount. Accepts BTC (default) or sats.
+export function parseAmount(value, unit) {
+  const n = Number(String(value).trim().replace(/,/g, ''));
+  if (!isFinite(n) || n < 0) return null;
+  return unit === 'sats' ? Math.round(n) : Math.round(n * SATS);
+}
+
+export function shortAddr(a, head = 10, tail = 8) {
+  if (!a || a.length <= head + tail + 1) return a;
+  return `${a.slice(0, head)}…${a.slice(-tail)}`;
+}
+
+export function shortTxid(t) {
+  return shortAddr(t, 8, 8);
+}
+
+export function timeAgo(unixSeconds) {
+  if (!unixSeconds) return 'pending';
+  const s = Math.max(0, Math.floor(Date.now() / 1000 - unixSeconds));
+  const units = [
+    [31536000, 'y'],
+    [2592000, 'mo'],
+    [86400, 'd'],
+    [3600, 'h'],
+    [60, 'm'],
+  ];
+  for (const [secs, label] of units) {
+    if (s >= secs) return `${Math.floor(s / secs)}${label} ago`;
+  }
+  return `${s}s ago`;
+}