@outfitter/typescript-config

Shared TypeScript configurations for consistent, strict type safety across Outfitter projects

Installation

npm install --save-dev @outfitter/typescript-config
# or
pnpm add -D @outfitter/typescript-config

Usage

Extend one of the provided configurations in your tsconfig.json:

Base Configuration (Recommended)

For general TypeScript projects:

{
  "extends": "@outfitter/typescript-config/base",
  "compilerOptions": {
    "outDir": "dist",
    "rootDir": "src"
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules", "dist"]
}

Next.js Configuration

For Next.js applications:

{
  "extends": "@outfitter/typescript-config/next",
  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx"],
  "exclude": ["node_modules"]
}

Vite Configuration

For Vite-based applications:

{
  "extends": "@outfitter/typescript-config/vite",
  "include": ["src", "vite.config.ts"],
  "exclude": ["node_modules", "dist"]
}

What's Included

Strict Type Safety

All configurations enforce maximum type safety:

• strict: true: Enables all strict type checking options
• noImplicitAny: true: No implicit any types allowed
• strictNullChecks: true: Null and undefined must be handled explicitly
• noUncheckedIndexedAccess: true: Array/object access returns T | undefined
• exactOptionalPropertyTypes: true: Optional properties can't be set to undefined

Modern JavaScript

• Target: ES2022 with ES2023 library features
• Module: ESNext with bundler resolution
• verbatimModuleSyntax: true: Explicit import/export syntax

Developer Experience

• Path Mapping: @/* maps to ./src/* by default
• Incremental Builds: Faster subsequent compilations
• Declaration Maps: Better IDE navigation to source

Code Quality

• noUnusedLocals: true: Catch unused variables
• noUnusedParameters: true: Catch unused function parameters
• noImplicitReturns: true: All code paths must return
• noFallthroughCasesInSwitch: true: Explicit break/return in switch cases

Configuration Details

Base Configuration

The strictest configuration for maximum type safety and code quality. Use this for:

• Libraries
• Node.js applications
• General TypeScript projects

Next.js Configuration

Extends base with Next.js-specific settings:

• JSX support for React
• Next.js module resolution
• Optimized for Next.js build system

Vite Configuration

Extends base with Vite-specific settings:

• JSX support for React
• Vite-compatible module resolution
• Client-side DOM types

Customization

Override any setting in your local tsconfig.json:

{
  "extends": "@outfitter/typescript-config/base",
  "compilerOptions": {
    // Example: Allow unused locals during development
    "noUnusedLocals": false,

    // Example: Custom paths
    "paths": {
      "@/*": ["./src/*"],
      "@components/*": ["./src/components/*"]
    }
  }
}

Best Practices

1. Don't disable strict checks: Work with the type system, not against it
2. Handle all cases: The configs force you to handle edge cases explicitly
3. Use path aliases: Keep imports clean with the @/* alias
4. Enable project references: For monorepos, use TypeScript project references

Migration Guide

For detailed instructions on migrating from a loose TypeScript configuration to strict settings, see the TypeScript Migration Guide.

Development

This package is part of the @outfitter/monorepo monorepo.

See the Development Guide for instructions on building, testing, and contributing to this package.

License

MIT