How to add basic TypeScript support

• Install typescript, and type declarations for Express and Node from @types/express and @types/node as dev dependencies.
  • Explicit type dependencies are only required for packages written in JS.
• Run npx tsc --init to generate the tsconfig.json file.
  • Specify outputDir in compilerOptions to specify the final output JS file path.
• Convert index.js to index.ts and import and add types for everything.
• Use npx ts-node ./src/index.ts to run typescript files.

Hot-reloading ts files

• Install nodemon and ts-node as dev dependencies and add the following scripts to package.json:
  • "build": "tsc"
  • "start": "node ./dist/index.js"
  • "dev": "nodemon ./src/index.ts"
• Run npm run dev to run and watch for changes.

ESLint support for TypeScript

• Follow setup instructions from https://typescript-eslint.io/getting-started
• Add eslint scripts to package.json:
  • "lint": "eslint src/\*\*/\*\.ts"
  • "format": "eslint src/\*\*/\*.ts --fix"