feat: today's fcc challenge

src/freecodecamp/daily/2025-11-21/main.spec.ts

@@ -0,0 +1,18 @@
+/**
+ * @copyright NHCarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+import { describe, it, expect } from "vitest";
+import { lcm } from "./main.js";
+
+describe("lcm", () => {
+    it("should return the correct LCM", () => {
+        expect(lcm(4, 6)).toBe(12);
+        expect(lcm(9, 6)).toBe(18);
+        expect(lcm(10, 100)).toBe(100);
+        expect(lcm(13, 17)).toBe(221);
+        expect(lcm(45, 70)).toBe(630);
+    });
+});

src/freecodecamp/daily/2025-11-21/main.ts

@@ -0,0 +1,20 @@
+/**
+ * @copyright NHCarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+const gcd = (firstNumber: number, secondNumber: number): number => {
+    return secondNumber === 0 ? firstNumber : gcd(secondNumber, firstNumber % secondNumber);
+};
+
+/**
+ * Given two integers, return the least common multiple (LCM) of the two numbers.
+ * @param firstNumber - The first integer.
+ * @param secondNumber - The second integer.
+ * @returns The least common multiple (LCM) of the two numbers.
+ * @see https://www.freecodecamp.org/learn/daily-coding-challenge/2025-11-21
+ */
+export const lcm = (firstNumber: number, secondNumber: number): number => {
+    return (firstNumber * secondNumber) / gcd(firstNumber, secondNumber);
+}