[Docs]: Include a GitHub repo with a minimal working demo

[martinsik]

🚀 Feature Proposal

It would be helpful if I could experiment with ts-jest in a independent project that is guaranteed to work and that I can just pull and run.

Motivation

I'm trying to implement ts-jest into an existing project but I'm not able to run a single test. Using just jest works but with ts-jest it looks like it doesn't even read my jest.config.ts. I suppose there's something with babel config or tsconfigs that are already in the project. Maybe TypeScript version or I don't know what is the issue.

When I run npx ts-jest I only get this response and it doesn't run any test:

Usage:
  ts-jest command [options] [...args]

Commands:
  config:init           Creates initial Jest configuration
  config:migrate        Migrates a given Jest configuration
  help [command]        Show this help, or help about a command

Example:
  ts-jest help config:migrate

Example

No response

[pjdon]

This would be good to have given that ts-jest works "out of the box".

If you're running into problems, here's what worked for me starting from an empty project folder:
(path / is project root)

1. Initialize a new NodeJS project

Run npm init -y

Creates file /package.json with the following contents. I've removed a few extra keys for brevity and added a test script that we'll need later.

{
  "name": "ts-testing",
  "scripts": {
    "test": "jest"
  },
  "devDependencies": {
    "@types/jest": "^29.5.12",
    "jest": "^29.7.0",
    "ts-jest": "^29.1.2",
    "typescript": "^5.4.3"
  }
}

2. Install dependencies step from ts-jest docs

Run npm install --save-dev jest typescript ts-jest @types/jest

3. From the next step in the page, create a ts-jest config

Run npx ts-jest config:init

Creates file /jest.config.js with the following contents.

module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
};

4. Create a new default typescript config

Run npx tsc -init (creates file /tsconfig.json)

Creates file /tsconfig.json with the following contents. I've removed the generate comments.

{
  "compilerOptions": {
    "target": "es2016",
    "module": "commonjs",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "skipLibCheck": true
  }
}

5. Create your typescript file

For example /calc.ts with the following contents.

export function add(a: number, b: number): number {
  return a + b;
}

6. Create your unit test file.

It should end in spec.ts. For example /calc.spec.ts with the following contents.

import { add } from "./calc";

describe("Addition", () => {
  test("Two integers", () => {
    expect(add(1, 2)).toBe(3);
  });
});

7. Start the tests

Run npm run test

Should get the following if you used the examples above

 PASS  ./calc.spec.ts
  Addition
    √ Two integers (2 ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total