Build

1. From the root of your repository, run npm init -y to create a new Node.js project.
2. Add TypeScript along with types for node:

npm install -D typescript @types/node

3. Configure TypeScript by creating a tsconfig.json file in the root of your project:

{
  "compilerOptions": {
    "target": "esnext",
    "module": "nodenext",
    "rootDir": "./src",
    "outDir": "./dist",
    "strict": true,
    "moduleResolution": "nodenext",
    "esModuleInterop": true,
    "skipLibCheck": true
  },
  "include": ["./src/**/*.ts"],
  "exclude": ["node_modules"]
}

• rootDir is where your TypeScript files are located
• outDir is where your compiled JavaScript files will go (you won't modify these - they're generated from your TypeScript files)
• include specifies the files to include in the compilation
• exclude specifies the files to exclude from the compilation
• strict enables all strict type checking options
• esModuleInterop allows you to use ES module syntax
• moduleResolution specifies how modules are resolved
• skipLibCheck skips type checking all declaration files

4. Configure the package.json in the root of your project:
   • add "type":"module". This means we can use the ES module syntax in our project for imports and exports.
   • add a build script that runs npx tsc - this will compile your TypeScript code to JavaScript.
   • add a start script that runs node dist/main.js - this will start the REPL.
   • add a dev script that runs a combination of the build and start scripts for convenience.

{
...
  "type": "module",
  "scripts": {
    "build": "npx tsc",
    "start": "node dist/main.js",
    "dev": "npx tsc && node dist/main.js"
  },
...
}

5. Add a .gitignore file to the root of your project and ensure it ignores the dist and node_modules directories.
6. Create a new src directory to put your project - this is where your TypeScript code will live.
7. In src/main.ts, create a main() function:

function main() {
  console.log("Hello, world!");
}

main();

8. To pass off this step, from the root of your project, run:

npm run dev

If you see "Hello, world!" printed in the console, you're good to go!

Run and submit the CLI tests.