How do I test modules in JavaScript?

How do I test modules in JavaScript?

You can test JavaScript modules using frameworks like Jest, Mocha, or Jasmine. Do you have a specific framework in mind?

I’m not sure. What’s the difference between Jest and Mocha?

Jest is a testing framework developed by Facebook, known for its simplicity and built-in mocking capabilities. Mocha is more flexible and allows you to choose your assertion library.

Can you show me a simple example using Jest?

Sure! Here’s a basic example:

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

// sum.test.js
const sum = require('./sum');

test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

Run jest in your terminal to execute the test.

That’s helpful! How do I set up Jest in my project?

You can set up Jest by running npm install --save-dev jest in your project directory. Then, add a test script in your package.json like this:

"scripts": {
  "test": "jest"
}