Base setup

Before we start configuring and installing dependencies, let's first create a base project:

mkdir your-project && cd your-project
mkdir src

Setup node project:

npm init --yes

Create project source code:

touch src/main.ts src/calc.ts

src/calc.ts:

export const add = (x: number, y: number) => x + y;

src/main.ts:

import * as fs from 'fs';
import { add } from './calc';

console.log(add(2,2));

fs.writeFile('text.txt', 'Content.', (err) => {
  if (err) throw err;
  console.log('File created.');
}); 

Setup TypeScript

Install typescript dev dependencies:

npm install typescript @types/node --save-dev

Init typescript:

tsc --init

And configure tsconfig.json to look like this:

{
  "compilerOptions": {
    "target": "ES2020",
    "module": "commonjs",
    "allowJs": true,
    "outDir": "dist",
    "rootDir": "src",
    "strict": true,
    "noImplicitAny": true,
    "esModuleInterop": true,
    "resolveJsonModule": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  }
}

Setup Nodemon

Install nodemon and ts-node as dev dependency:

npm install --save-dev ts-node nodemon

Create nodemon configuration file:

touch nodemon.json

nodemon.json:

{
  "watch": ["src"],
  "ext": ".ts,.js",
  "ignore": [],
  "exec": "ts-node ./src/main.ts"
}

Add a start:dev script to package.json:

...
"start:dev": "nodemon"
...

Now if you run npm run start:dev everything should work.

Before we wrap up, it would be great to add production scripts.

First install rimraf as dev dependency:

npm install --save-dev rimraf

rimraf - Deletes all files and folders at "path", recursively.

after, add this two scripts to package.json:

...
"build:prod": "rimraf ./dist && tsc",
"start:prod": "npm run build:prod && node dist/main.js"
...

Now run command npm run start:prod