feat: add least common multiple algorithm

Maths/LeastCommonMultiple.js

@@ -0,0 +1,26 @@
+/**
+ * @function leastCommonMultiple
+ * @description Finds the least common multiple (LCM) of two positive
+ *   integers using the relationship: LCM(a, b) = (a * b) / GCD(a, b).
+ * @param {number} a - First positive integer
+ * @param {number} b - Second positive integer
+ * @returns {number} - The LCM of a and b
+ * @see https://en.wikipedia.org/wiki/Least_common_multiple
+ * @example leastCommonMultiple(4, 6) => 12
+ * @example leastCommonMultiple(12, 15) => 60
+ * @example leastCommonMultiple(7, 5) => 35
+ */
+const leastCommonMultiple = (a, b) => {
+  if (!Number.isInteger(a) || !Number.isInteger(b) || a < 1 || b < 1) {
+    throw new TypeError('Both inputs must be positive integers')
+  }
+  const gcd = (x, y) => {
+    while (y !== 0) {
+      ;[x, y] = [y, x % y]
+    }
+    return x
+  }
+  return (a * b) / gcd(a, b)
+}
+
+export { leastCommonMultiple }

Maths/test/LeastCommonMultiple.test.js

@@ -0,0 +1,43 @@
+import { leastCommonMultiple } from '../LeastCommonMultiple.js'
+
+describe('leastCommonMultiple', () => {
+  test('leastCommonMultiple(4, 6) returns 12', () => {
+    expect(leastCommonMultiple(4, 6)).toBe(12)
+  })
+
+  test('leastCommonMultiple(12, 15) returns 60', () => {
+    expect(leastCommonMultiple(12, 15)).toBe(60)
+  })
+
+  test('leastCommonMultiple(7, 5) returns 35', () => {
+    expect(leastCommonMultiple(7, 5)).toBe(35)
+  })
+
+  test('leastCommonMultiple(1, 1) returns 1', () => {
+    expect(leastCommonMultiple(1, 1)).toBe(1)
+  })
+
+  test('leastCommonMultiple of same numbers returns that number', () => {
+    expect(leastCommonMultiple(5, 5)).toBe(5)
+  })
+
+  test('leastCommonMultiple(3, 4) returns 12', () => {
+    expect(leastCommonMultiple(3, 4)).toBe(12)
+  })
+
+  test('leastCommonMultiple(100, 75) returns 300', () => {
+    expect(leastCommonMultiple(100, 75)).toBe(300)
+  })
+
+  test('throws TypeError for zero input', () => {
+    expect(() => leastCommonMultiple(0, 5)).toThrow(TypeError)
+  })
+
+  test('throws TypeError for negative input', () => {
+    expect(() => leastCommonMultiple(-4, 6)).toThrow(TypeError)
+  })
+
+  test('throws TypeError for float input', () => {
+    expect(() => leastCommonMultiple(4.5, 6)).toThrow(TypeError)
+  })
+})