TypeScript - Installation & Toolchain

Install TypeScript

npm init -y
npm install --save-dev typescript
npx tsc --init

This creates tsconfig.json. You'll tune it later in the tsconfig Deep Dive.

Compiling

• tsc: Official compiler, typechecks and can emit JS.
• tsx: Fast runner for TS/ESM without config; great for scripts.
• esbuild/tsup/swc: Extremely fast bundlers/transpilers; often paired with tsc for typechecking.
• Vite/Rollup/Webpack: App bundlers with TS support via plugins/loaders.

Scripts

{
  "scripts": {
    "build": "tsc -p tsconfig.json",
    "watch": "tsc -w",
    "dev": "tsx src/index.ts",
    "typecheck": "tsc -p tsconfig.json --noEmit"
  }
}

Recommended tsconfig starting point

{
  "compilerOptions": {
    "target": "ES2020",
    "module": "ESNext",
    "moduleResolution": "bundler",
    "strict": true,
    "noUncheckedIndexedAccess": true,
    "exactOptionalPropertyTypes": true,
    "skipLibCheck": true,
    "jsx": "react-jsx",
    "outDir": "dist",
    "rootDir": "src"
  },
  "include": ["src"]
}

Node ESM/CJS

Decide ESM vs CJS per project. For ESM in Node, set "type": "module" in package.json and use NodeNext resolutions when needed. We'll deep dive later.