Getting Started

import { PackageManagers } from "starlight-package-managers";

1. Installation

First, install the mocha package as a devDependency using your favorite package manager:

:::note As of v11.0.0, Mocha requires Node.js ^18.18.0 || ^20.9.0 || >=21.1.0. :::

2. Test File

Create the following example.test.js file under a test/ directory:

// test/example.test.js
import { assert } from "node:assert";

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

3. Running Mocha

Now, run npx mocha to execute the Mocha package on the newly created test file:

npx mocha

You should see passing output like:

  Array
    #indexOf()
      ✓ should return -1 when the value is not present

  1 passing (9ms)

Optional: test script

Most projects include a package.json "test" script:

// package.json
{
  "scripts": {
    "test": "mocha"
  }
}

You can then run that script with your favorite package manager:

Next Steps

See:

• CLI for the commands you can pass to mocha
• Configuring for creating a persistent test configuration file
• Editor Plugins for improving the Mocha experience in your editor

You can see real live example code in our example repositories:

• Mocha examples
• Express
• Connect
• SuperAgent
• WebSocket.io
• Mocha tests