Node.js 18 introduced a native test runner that eliminates the need for jest, mocha or vitest in basic scenarios. We’ve been using it exclusively for the past couple of weeks with great success.

Configuration

The test script in package.json:

{
  "scripts": {
    "test": "node --import global-jsdom/register --import tsx --experimental-transform-types --experimental-test-module-mocks --test"
  }
}

Flag breakdown:

• --import tsx: Handles TypeScript compilation
• --import global-jsdom/register: Provides DOM environment for React components
• --experimental-transform-types: Strips TypeScript types during execution
• --experimental-test-module-mocks: Enables module mocking
• --test: Activates Node’s test runner

Dependencies

Required dev dependencies:

pnpm add --save-dev @testing-library/react global-jsdom jsdom tsx

TypeScript Unit Tests

import { describe, test } from "node:test";
import { strict as assert } from "node:assert";
import { getInitials } from "./stringUtils";

describe("String Utils", () => {
  test("should return correct initials", () => {
    const result = getInitials("John Smith");
    assert.equal(result, "JS");
  });
});

Uses Node’s built-in assert module for assertions.

React Component Testing

React Testing Library can still work with jsdom to provide a DOM.

import React from "react";
import { describe, test } from "node:test";
import { strict as assert } from "node:assert";
import { render, fireEvent, screen, cleanup } from "@testing-library/react";
import { Toggle } from "./Toggle";

beforeEach(() => {
  cleanup(); // cleans the dom state between each test
});

describe("Toggle", () => {
  test("calls onToggleClick when clicked", () => {
    let callCount = 0;
    const { getByText } = render(
      <Toggle 
        options={["On", "Off"]}
        selected="On"
        onToggleClick={() => callCount++}
      />
    );
    
    fireEvent.click(getByText("On"));
    assert.equal(callCount, 1);
  });
});

Running Tests

# All tests
pnpm test

# Watch mode
pnpm test -- --watch

# Specific file
node --import global-jsdom/register --import tsx --experimental-transform-types --test src/components/Toggle.test.tsx

Comparison

Advantages:

• No configuration files required
• Direct TypeScript execution
• Built into Node.js runtime
• Smaller dependency footprint

Limitations:

• Requires Node 18+
• Uses experimental flags
• Smaller ecosystem than Jest, vitest, etc. This means fewer examples