lcm.js file added

Author: pranav.date

Maths/LCM.js

@@ -0,0 +1,36 @@
+/**
+ * @function lcm
+ * @description Compute the least common multiple (LCM) of two integers.
+ * @param {number} a - first integer
+ * @param {number} b - second integer
+ * @return {number} LCM of a and b
+ * @example lcm(4,6) -> 12
+ * @example lcm(7,3) -> 21
+ */
+const gcd = (x, y) => {
+  let a = Math.abs(x)
+  let b = Math.abs(y)
+  if (Number.isNaN(a) || Number.isNaN(b)) throw new TypeError('Argument is NaN - Not a Number')
+  while (b !== 0) {
+    const t = a % b
+    a = b
+    b = t
+  }
+  return a
+}
+
+const lcm = (a, b) => {
+  const na = Number(a)
+  const nb = Number(b)
+
+  if (Number.isNaN(na) || Number.isNaN(nb) || typeof a === 'object' || typeof b === 'object') {
+    throw new TypeError('Argument is NaN - Not a Number')
+  }
+
+  if (na === 0 || nb === 0) return 0
+
+  // lcm(a,b) = |a * b| / gcd(a,b)
+  return Math.abs((na / gcd(na, nb)) * nb)
+}
+
+export { lcm }

Maths/test/LCM.test.js

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+import { describe, it, expect } from 'vitest'
+import { lcm } from '../LCM'
+
+describe('lcm()', () => {
+  it('returns 0 when either argument is 0', () => {
+    expect(lcm(0, 5)).toBe(0)
+    expect(lcm(7, 0)).toBe(0)
+  })
+
+  it('computes LCM for positive integers', () => {
+    expect(lcm(4, 6)).toBe(12)
+    expect(lcm(7, 3)).toBe(21)
+    expect(lcm(21, 6)).toBe(42)
+  })
+
+  it('computes LCM when inputs are negative', () => {
+    expect(lcm(-4, 6)).toBe(12)
+    expect(lcm(4, -6)).toBe(12)
+    expect(lcm(-4, -6)).toBe(12)
+  })
+
+  it('throws for non-numeric inputs', () => {
+    // @ts-ignore
+    expect(() => lcm('a', 5)).toThrow()
+    // @ts-ignore
+    expect(() => lcm(4, {})).toThrow()
+  })
+})