How do I use Mocha and Chai for testing in JavaScript?

How do I use Mocha and Chai for testing in JavaScript?

Mocha is a test framework for Node.js, and Chai is an assertion library. You can use them together to write tests.

Can you show me a simple example of a test using Mocha and Chai?

Sure! Here's a basic example:

const chai = require('chai');
const expect = chai.expect;

describe('Array', function() {
  describe('#indexOf()', function() {
    it('should return -1 when the value is not present', function() {
      expect([1, 2, 3].indexOf(4)).to.equal(-1);
    });
  });
});

What are some common assertions I can use with Chai?

Chai provides several assertion styles. Common ones include:

• expect(value).to.equal(expected)
• should.exist(value)
• assert.isTrue(value) You can choose the style that fits your preference!

How do I run my tests once I've written them?

You can run your tests by using the command mocha in your terminal. Make sure you have Mocha installed globally or in your project.