1 files changed, 31 insertions, 0 deletions
diff --git a/frontend/lib/format.ts b/frontend/lib/format.ts
new file mode 100644
index 0000000..34bffd8
--- /dev/null
+++ b/frontend/lib/format.ts
@@ -0,0 +1,31 @@
+export function fmtCurrency(value?: number | null, decimals = 2): string {
+  if (value === null || value === undefined || Number.isNaN(value)) return "-";
+  return `$${value.toLocaleString(undefined, { maximumFractionDigits: decimals, minimumFractionDigits: decimals })}`;
+}
+
+export function fmtNumber(value?: number | null, decimals = 2): string {
+  if (value === null || value === undefined || Number.isNaN(value)) return "-";
+  return value.toLocaleString(undefined, { maximumFractionDigits: decimals, minimumFractionDigits: decimals });
+}
+
+export function fmtLarge(value?: number | null): string {
+  if (value === null || value === undefined || Number.isNaN(value)) return "-";
+  const abs = Math.abs(value);
+  const sign = value < 0 ? "-" : "";
+  if (abs >= 1e12) return `${sign}$${(abs / 1e12).toFixed(2)}T`;
+  if (abs >= 1e9) return `${sign}$${(abs / 1e9).toFixed(2)}B`;
+  if (abs >= 1e6) return `${sign}$${(abs / 1e6).toFixed(1)}M`;
+  return `${sign}$${abs.toLocaleString(undefined, { maximumFractionDigits: 0 })}`;
+}
+
+export function fmtPct(value?: number | null, decimals = 2, signed = false): string {
+  if (value === null || value === undefined || Number.isNaN(value)) return "-";
+  const pct = value * 100;
+  const sign = signed && pct > 0 ? "+" : "";
+  return `${sign}${pct.toFixed(decimals)}%`;
+}
+
+export function deltaClass(value?: number | null): string {
+  if (value === null || value === undefined) return "neutral";
+  return value >= 0 ? "positive" : "negative";
+}