---
name: implement-is-odd
description: Implement isOdd following test-driven development
---

# Implement isOdd (test-driven)

Implement `isOdd(n)` in `src/isodd.js` as a named ESM export. It returns whether
an integer is odd.

Follow test-driven development, in this order:

1. **First** write a failing test in `test/isodd.test.js`.
2. **Then** implement `src/isodd.js` to make the test pass.

Do not write the implementation before the test exists and fails.