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TypeScript Setup

npm stands for "Node Package Manager". By installing Node.js, you've gained some new commands:

node - The JavaScript runtime. This will let you run your application files.
npm - The package manager. This manages dependencies, metadata, and allows you to specify "scripts" to run.
npx - The package runner. Run a command from a local or remote npm package.

Most TS devs don't run the node commands directly, they use it within an npm script.

Assignment

Start a new node project with this command:

npm init

This command will prompt you with a series of questions. For this project, you can either press Enter for the recommended defaults or follow the prompts.

Add TypeScript along with types for node, and tsx (TypeScript Execute) which will allow you to run TypeScript files directly in Node.js:

npm install -D typescript @types/node tsx

Create a src directory at the root of your project and create a file inside named index.ts. Add a console.log command to the file that prints "Hello, World!". This file will be the entry point.

console.log("Hello, World!");

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

{
  "compilerOptions": {
    "target": "esnext",
    "module": "esnext",
    "strict": true,
    "moduleResolution": "Node"
  },
  "include": ["./src/**/*.ts"],
  "exclude": ["node_modules"]
}

Edit the package.json file that was created during npm init. The scripts section should have something like:

...
  "type": "module",
  "scripts": {
    "start": "tsx ./src/index.ts"
  },
...

This enables your project to use ES modules and adds a "start" script to this project that runs index.ts using the tsx typescript executable.

With all that ready to go, simply run:

npm start

And you should see your "hello world" message logged to the console!

.gitignore

A .gitignore file is used to tell Git which files or folders to ignore when committing changes to a repository. This is useful for ignoring files that are specific to your local development environment or files that should not be tracked in the repository, such as compiled files or sensitive information.

Create a .gitignore file at the project root (with the leading period). Have git ignore the node_modules/ directory.

Submit the CLI tests from your project's root. There's no penalty on failure for this lesson.