{
  // Compiler behavior — the bulk of configuration
  "compilerOptions": {
    "target": "ES2022",               // JavaScript version to emit
    "module": "NodeNext",             // Module system for output
    "moduleResolution": "NodeNext",   // How imports are resolved
    "strict": true,                   // Enable all strict type-checking
    "esModuleInterop": true,          // Allow default imports from CJS
    "declaration": true,              // Generate .d.ts files
    "declarationMap": true,           // Source maps for .d.ts files
    "sourceMap": true,                // Source maps for .js files
    "outDir": "./dist",              // Output directory
    "rootDir": "./src",              // Root of source files
    "baseUrl": ".",                   // Base for non-relative imports
    "paths": {                        // Path aliases
      "@/*": ["./src/*"]
    },
    "lib": ["ES2022"],               // Runtime library type definitions
    "isolatedModules": true,          // Ensure each file can be transpiled independently
    "verbatimModuleSyntax": true,     // Enforce explicit type-only imports
    "noUncheckedIndexedAccess": true, // Index signatures include undefined
    "skipLibCheck": true              // Skip .d.ts type checking for speed
  },

  // Files to include in compilation
  "include": ["src/**/*.ts", "src/**/*.tsx"],

  // Files to exclude from compilation
  "exclude": ["node_modules", "dist", "**/*.test.ts"],

  // Project references for monorepos
  "references": [
    { "path": "../shared" },
    { "path": "../utils" }
  ]
}

# Type-check only
tsc --noEmit

# Build with a bundler
vite build        # for apps
tsup src/index.ts # for libraries

// vite.config.ts
import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import tsconfigPaths from "vite-tsconfig-paths";

export default defineConfig({
  plugins: [
    react(),
    tsconfigPaths(), // resolves tsconfig paths aliases
  ],
  build: {
    target: "ES2022",
    sourcemap: true,
  },
  server: {
    port: 3000,
    open: true,
  },
});

// tsup.config.ts
import { defineConfig } from "tsup";

export default defineConfig({
  entry: ["src/index.ts"],
  format: ["cjs", "esm"],      // dual output
  dts: true,                    // generate .d.ts
  sourcemap: true,
  clean: true,                  // clean dist/ before build
  splitting: false,             // no code splitting for libraries
  target: "ES2022",
  outDir: "dist",
  treeshake: true,
  // External dependencies (not bundled)
  external: ["react", "react-dom"],
});

// build.config.ts
import { defineBuildConfig } from "unbuild";

export default defineBuildConfig({
  entries: ["src/index"],
  declaration: true,
  rollup: {
    emitCJS: true,
  },
  externals: ["react"],
});

// packages/shared/tsconfig.json
{
  "compilerOptions": {
    "composite": true,        // required for project references
    "declaration": true,       // implied by composite
    "declarationMap": true,    // enables "go to definition" across packages
    "outDir": "./dist",
    "rootDir": "./src"
  },
  "include": ["src/**/*.ts"]
}

// tsconfig.json (root)
{
  "files": [],                  // root does not compile anything itself
  "references": [
    { "path": "packages/shared" },
    { "path": "packages/api" },
    { "path": "packages/web" }
  ]
}

// packages/api/tsconfig.json
{
  "compilerOptions": {
    "composite": true,
    "outDir": "./dist",
    "rootDir": "./src"
  },
  "references": [
    { "path": "../shared" }
  ],
  "include": ["src/**/*.ts"]
}

# Build all referenced projects in dependency order
tsc --build

# Build with verbose output
tsc --build --verbose

# Clean all build outputs
tsc --build --clean

# Force full rebuild
tsc --build --force

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "@/*": ["./src/*"],
      "@components/*": ["./src/components/*"],
      "@utils/*": ["./src/utils/*"]
    }
  }
}

{
  "compilerOptions": {
    "declaration": true,         // emit .d.ts files
    "declarationMap": true,      // emit .d.ts.map for "go to source"
    "declarationDir": "./dist",  // where to put .d.ts files
    "emitDeclarationOnly": true  // only emit .d.ts, no .js (when bundler handles JS)
  }
}

// package.json
{
  "name": "my-lib",
  "type": "module",
  "exports": {
    ".": {
      "types": "./dist/index.d.ts",
      "import": "./dist/index.mjs",
      "require": "./dist/index.cjs"
    }
  },
  "types": "./dist/index.d.ts",
  "main": "./dist/index.cjs",
  "module": "./dist/index.mjs"
}

# Type-check without emitting — fastest way to validate types in CI
tsc --noEmit

# With incremental caching for faster re-runs
tsc --noEmit --incremental

{
  "compilerOptions": {
    "incremental": true,
    "tsBuildInfoFile": "./.tsbuildinfo"
  }
}

# Watch and type-check continuously during development
tsc --noEmit --watch

# Watch with project references
tsc --build --watch

# In package.json scripts
{
  "scripts": {
    "build": "tsup src/index.ts",
    "typecheck": "tsc --noEmit",
    "ci": "npm run typecheck && npm run build && npm run test"
  }
}