fix: clamp decimals in format utils to prevent RangeError crash

src/lib/utils.ts

@@ -28,10 +28,10 @@ export function formatAmount(
   const abs = Math.abs(num);
   // Tiny positive numbers: show '< 0.0001' for values > 0 and < 0.0001
   if (abs > 0 && abs < 0.0001) return `< 0.0001`;
-  // Cap maximum decimals to 4 to avoid very long fractional displays
+  // Cap decimals to valid range (0-4) and ensure min <= max
   const maxDecimals = Math.min(4, Math.max(0, decimals));
   return num.toLocaleString("en-US", {
-    minimumFractionDigits: 2,
+    minimumFractionDigits: Math.min(2, maxDecimals),
     maximumFractionDigits: maxDecimals,
   });
 }
@@ -51,9 +51,10 @@ export function formatCurrency(
     return `${currencySymbol}${abbreviateNumber(num, 1)}`;
   }
   // For smaller numbers, show with requested decimals (no grouping abbreviation)
+  const safeDecimals = Math.max(0, decimals);
   return `${currencySymbol}${num.toLocaleString("en-US", {
-    minimumFractionDigits: decimals,
-    maximumFractionDigits: decimals,
+    minimumFractionDigits: safeDecimals,
+    maximumFractionDigits: safeDecimals,
   })}`;
 }
 
@@ -64,9 +65,10 @@ export function formatPercent(
   if (value === null || value === undefined) return `0%`;
   const num = Number(value);
   if (!Number.isFinite(num)) return `0%`;
+  const safeDecimals = Math.max(0, decimals);
   return `${Number(value).toLocaleString("en-US", {
-    minimumFractionDigits: decimals,
-    maximumFractionDigits: decimals,
+    minimumFractionDigits: safeDecimals,
+    maximumFractionDigits: safeDecimals,
   })}%`;
 }
 

test/lib/utils.test.ts

@@ -80,6 +80,21 @@ describe("formatAmount", () => {
     it("should respect custom decimals", () => {
         expect(formatAmount(1.123456, 2)).toBe("1.12");
     });
+
+    it("should not throw RangeError when decimals is 0", () => {
+        expect(() => formatAmount(100000, 0)).not.toThrow();
+        expect(formatAmount(100000, 0)).toBe("100,000");
+    });
+
+    it("should not throw RangeError when decimals is 1", () => {
+        expect(() => formatAmount(1234.5, 1)).not.toThrow();
+        expect(formatAmount(1234.5, 1)).toBe("1,234.5");
+    });
+
+    it("should not throw RangeError when decimals is negative", () => {
+        expect(() => formatAmount(1234, -1)).not.toThrow();
+        expect(formatAmount(1234, -1)).toBe("1,234");
+    });
 });
 
 describe("formatCurrency", () => {
@@ -110,6 +125,16 @@ describe("formatCurrency", () => {
     it("should not abbreviate when disabled", () => {
         expect(formatCurrency(5000, 2, "$", false)).toBe("$5,000.00");
     });
+
+    it("should not throw RangeError when decimals is 0", () => {
+        expect(() => formatCurrency(100, 0)).not.toThrow();
+        expect(formatCurrency(100, 0, "$", false)).toBe("$100");
+    });
+
+    it("should not throw RangeError when decimals is negative", () => {
+        expect(() => formatCurrency(100, -1)).not.toThrow();
+        expect(formatCurrency(100, -1, "$", false)).toBe("$100");
+    });
 });
 
 describe("formatPercent", () => {
@@ -132,6 +157,11 @@ describe("formatPercent", () => {
     it("should respect custom decimals", () => {
         expect(formatPercent(33.3333, 1)).toBe("33.3%");
     });
+
+    it("should not throw RangeError when decimals is negative", () => {
+        expect(() => formatPercent(50, -1)).not.toThrow();
+        expect(formatPercent(50, -1)).toBe("50%");
+    });
 });
 
 describe("maskString", () => {