How can I test modular code in Node.js?

How can I test modular code in Node.js?

You can use testing frameworks like Mocha or Jest to test your modular code in Node.js. Would you like a code example?

Yes, please provide a simple example using Jest.

Sure! First, install Jest using npm. Then, create a module and a test file. Here's a basic example:

// math.js function add(a, b) { return a + b; } module.exports = add;

// math.test.js const add = require('./math'); test('adds 1 + 2 to equal 3', () => { expect(add(1, 2)).toBe(3); });

Run the test with the command 'jest'.

What if I want to test asynchronous code?

For asynchronous code, you can use async/await in your tests. Here's an example:

// fetchData.js const fetchData = async () => { return 'data'; };

module.exports = fetchData;

// fetchData.test.js const fetchData = require('./fetchData'); test('fetches data', async () => { const data = await fetchData(); expect(data).toBe('data'); });