TypeScript Setup and Configuration

# Using npm
npm install -g typescript

# Using yarn
yarn global add typescript

# Using pnpm
pnpm add -g typescript

# Verify installation
tsc --version

# Using npm
npm install --save-dev typescript

# Using yarn
yarn add --dev typescript

# Using pnpm
pnpm add -D typescript

# Create project directory
mkdir my-typescript-project
cd my-typescript-project

# Initialize package.json
npm init -y

# Install TypeScript
npm install --save-dev typescript

# Install Node.js types (for Node.js projects)
npm install --save-dev @types/node

# Generate tsconfig.json
npx tsc --init

my-typescript-project/
├── src/
│   ├── index.ts
│   └── utils/
│       └── helpers.ts
├── dist/
├── node_modules/
├── package.json
├── tsconfig.json
└── README.md

{
  "compilerOptions": {
    "target": "ES2020",
    "module": "commonjs",
    "outDir": "./dist",
    "rootDir": "./src",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "resolveJsonModule": true,
    "declaration": true,
    "declarationMap": true,
    "sourceMap": true
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules", "dist", "**/*.test.ts"]
}

{
  "compilerOptions": {
    // Target JavaScript version
    "target": "ES2020", // ES5, ES6, ES2017, ES2018, ES2019, ES2020, ES2021, ESNext

    // Module system
    "module": "commonjs", // commonjs, amd, es6, es2015, es2020, esnext

    // Output directory
    "outDir": "./dist",

    // Root directory of source files
    "rootDir": "./src",

    // Library files to include
    "lib": ["ES2020", "DOM"],

    // Module resolution strategy
    "moduleResolution": "node"
  }
}

{
  "compilerOptions": {
    // Enable all strict type checking options
    "strict": true,

    // Individual strict options (enabled by "strict")
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictBindCallApply": true,
    "strictPropertyInitialization": true,
    "noImplicitReturns": true,
    "noImplicitThis": true,
    "alwaysStrict": true,

    // Additional checks
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "exactOptionalPropertyTypes": true,
    "noImplicitOverride": true,
    "noPropertyAccessFromIndexSignature": true,
    "noUncheckedIndexedAccess": true
  }
}

{
  "compilerOptions": {
    // Generate source maps for debugging
    "sourceMap": true,

    // Generate declaration files
    "declaration": true,
    "declarationMap": true,

    // Remove comments from output
    "removeComments": false,

    // Import helpers from tslib
    "importHelpers": true,

    // Enable experimental decorators
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  }
}

# Compile all files
npx tsc

# Compile specific file
npx tsc src/index.ts

# Compile with custom config
npx tsc --project tsconfig.prod.json

# Watch for changes and recompile
npx tsc --watch

# Watch with custom config
npx tsc --watch --project tsconfig.dev.json

{
  "scripts": {
    "build": "tsc",
    "build:watch": "tsc --watch",
    "build:prod": "tsc --project tsconfig.prod.json",
    "clean": "rm -rf dist",
    "dev": "ts-node src/index.ts",
    "start": "node dist/index.js"
  }
}

# Install ts-node
npm install --save-dev ts-node

# Run TypeScript file directly
npx ts-node src/index.ts

# With nodemon for auto-restart
npm install --save-dev nodemon

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

{
  "typescript.preferences.importModuleSpecifier": "relative",
  "typescript.suggest.autoImports": true,
  "typescript.updateImportsOnFileMove.enabled": "always",
  "editor.codeActionsOnSave": {
    "source.organizeImports": true
  },
  "files.exclude": {
    "**/node_modules": true,
    "**/dist": true
  }
}

{
  "version": "2.0.0",
  "tasks": [
    {
      "type": "typescript",
      "tsconfig": "tsconfig.json",
      "option": "watch",
      "problemMatcher": ["$tsc-watch"],
      "group": "build",
      "label": "TypeScript: Watch"
    }
  ]
}

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "sourceMap": true,
    "removeComments": false,
    "noUnusedLocals": false,
    "noUnusedParameters": false
  },
  "include": ["src/**/*", "tests/**/*"]
}

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "sourceMap": false,
    "removeComments": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true
  },
  "exclude": ["node_modules", "tests", "**/*.test.ts", "**/*.spec.ts"]
}

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

// Instead of
import { helper } from "../../../utils/helper";

// Use
import { helper } from "@utils/helper";

# Install missing type definitions
npm install --save-dev @types/node
npm install --save-dev @types/express

{
  "compilerOptions": {
    "types": ["node"],
    "typeRoots": ["./node_modules/@types"]
  }
}

{
  "compilerOptions": {
    "module": "commonjs",
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true
  }
}