Configuration & Tooling

Understanding TypeScript's configuration options and tooling ecosystem is crucial for building robust applications. Let's explore how to configure and optimize your TypeScript projects!

tsconfig.json

The tsconfig.json file is the heart of a TypeScript project. It specifies the compiler options and project settings.

{
  "compilerOptions": {
    // Basic Options
    "target": "es2020",        // ECMAScript target version
    "module": "commonjs",      // Module code generation
    "outDir": "./dist",        // Output directory
    "rootDir": "./src",        // Root directory of source files

    // Strict Type-Checking
    "strict": true,            // Enable all strict type checking options
    "noImplicitAny": true,     // Raise error on expressions with implied 'any'
    "strictNullChecks": true,  // Enable strict null checks

    // Module Resolution
    "moduleResolution": "node",
    "baseUrl": "./",           // Base directory for resolving non-relative module names
    "paths": {                 // Path mapping for module aliases
      "@/*": ["src/*"]
    },

    // Additional Checks
    "noUnusedLocals": true,    // Report errors on unused locals
    "noUnusedParameters": true // Report errors on unused parameters
  },
  "include": ["src/**/*"],     // Files to include
  "exclude": ["node_modules"]  // Files to exclude
}

Compiler Options

Here are some important compiler options explained:

Type Checking

{
  "compilerOptions": {
    "strict": true,                // Enables all strict type checking options
    "noImplicitAny": true,        // Raise error on implied 'any' type
    "strictNullChecks": true,     // Enable strict null checks
    "strictFunctionTypes": true,   // Enable strict checking of function types
    "strictPropertyInitialization": true // Ensure class properties are initialized
  }
}

Source Maps & Debugging

{
  "compilerOptions": {
    "sourceMap": true,        // Generate source maps
    "declarationMap": true,   // Generate source maps for .d.ts files
    "inlineSourceMap": false  // Embed sourcemap in output file
  }
}

Build Tools

tsc (TypeScript Compiler)

The TypeScript compiler is your primary build tool:

# Compile the project
tsc

# Watch mode
tsc --watch

# Check types without emitting files
tsc --noEmit

Integration with Other Tools

Webpack

// webpack.config.js
module.exports = {
  entry: './src/index.ts',
  module: {
    rules: [
      {
        test: /\.tsx?$/,
        use: 'ts-loader',
        exclude: /node_modules/
      }
    ]
  },
  resolve: {
    extensions: ['.tsx', '.ts', '.js']
  }
};

ESLint

// .eslintrc.js
module.exports = {
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  extends: [
    'eslint:recommended',
    'plugin:@typescript-eslint/recommended'
  ]
};

Editor Support

TypeScript has excellent editor support, especially in VS Code:

1. IntelliSense

   • Auto-completion
   • Parameter hints
   • Quick info
   • Member lists

2. Refactoring Tools

   • Rename symbol
   • Extract function
   • Move to file

3. Code Navigation

   • Go to definition
   • Find all references
   • Symbol search

Best Practices

1. Start Strict

   • Enable strict: true from the beginning
   • It's harder to add strict checks later

2. Use Project References

   {
     "references": [
       { "path": "./tsconfig.shared.json" },
       { "path": "./tsconfig.server.json" }
     ]
   }

3. Optimize Build Performance

   • Use incremental: true
   • Enable skipLibCheck
   • Configure appropriate include/exclude

4. Version Control

   • Always commit tsconfig.json
   • Consider committing tsconfig.tsbuildinfo for incremental builds

Remember that good TypeScript configuration is a balance between type safety and development experience. Start with strict settings and adjust based on your team's needs.