ran npm run tdd & generated TDD

test/lcm/lcm.js

@@ -0,0 +1,5 @@
+module.exports = (...arr) => {
+const gcd = (x, y) => (!y ? x : gcd(y, x % y));
+const _lcm = (x, y) => x * y / gcd(x, y);
+return [...arr].reduce((a, b) => _lcm(a, b));
+};