From 5a69a9cf5067254db9484033ebc97e024eb49de9 Mon Sep 17 00:00:00 2001
From: sarthakgupta1907-cell <sarthakgupta1907@gmail.com>
Date: Sat, 7 Nov 2026 10:59:11 +0530
Subject: [PATCH] feat: add digit product algorithm

---
 Maths/DigitProduct.js           | 20 ++++++++++++++
 Maths/test/DigitProduct.test.js | 47 +++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 Maths/DigitProduct.js
 create mode 100644 Maths/test/DigitProduct.test.js

diff --git a/Maths/DigitProduct.js b/Maths/DigitProduct.js
new file mode 100644
index 0000000000..910b221768
--- /dev/null
+++ b/Maths/DigitProduct.js
@@ -0,0 +1,20 @@
+/**
+ * @function digitProduct
+ * @description Calculates the product of all digits of a given integer.
+ * @param {number} n - A non-negative integer
+ * @returns {number} - The product of all digits
+ * @see https://en.wikipedia.org/wiki/Multiplicative_digital_root
+ * @example digitProduct(123) => 6
+ * @example digitProduct(999) => 729
+ * @example digitProduct(0) => 0
+ */
+const digitProduct = (n) => {
+  if (!Number.isInteger(n) || n < 0) {
+    throw new TypeError('Input must be a non-negative integer')
+  }
+  return String(n)
+    .split('')
+    .reduce((product, d) => product * Number(d), 1)
+}
+
+export { digitProduct }
diff --git a/Maths/test/DigitProduct.test.js b/Maths/test/DigitProduct.test.js
new file mode 100644
index 0000000000..ade5f74fe7
--- /dev/null
+++ b/Maths/test/DigitProduct.test.js
@@ -0,0 +1,47 @@
+import { digitProduct } from '../DigitProduct.js'
+
+describe('digitProduct', () => {
+  test('digitProduct(0) returns 0', () => {
+    expect(digitProduct(0)).toBe(0)
+  })
+
+  test('digitProduct(1) returns 1', () => {
+    expect(digitProduct(1)).toBe(1)
+  })
+
+  test('digitProduct(123) returns 6', () => {
+    expect(digitProduct(123)).toBe(6)
+  })
+
+  test('digitProduct(999) returns 729', () => {
+    expect(digitProduct(999)).toBe(729)
+  })
+
+  test('digitProduct(111) returns 1', () => {
+    expect(digitProduct(111)).toBe(1)
+  })
+
+  test('digitProduct(100) returns 0', () => {
+    expect(digitProduct(100)).toBe(0)
+  })
+
+  test('digitProduct(99) returns 81', () => {
+    expect(digitProduct(99)).toBe(81)
+  })
+
+  test('digitProduct(555) returns 125', () => {
+    expect(digitProduct(555)).toBe(125)
+  })
+
+  test('throws TypeError for negative input', () => {
+    expect(() => digitProduct(-123)).toThrow(TypeError)
+  })
+
+  test('throws TypeError for float input', () => {
+    expect(() => digitProduct(1.5)).toThrow(TypeError)
+  })
+
+  test('throws TypeError for string input', () => {
+    expect(() => digitProduct('123')).toThrow(TypeError)
+  })
+})