Monorepo Management

Build efficient, scalable monorepos that enable code sharing, consistent tooling, and atomic changes across multiple packages and applications.

When to Use This Skill

• Setting up new monorepo projects
• Migrating from multi-repo to monorepo
• Optimizing build and test performance
• Managing shared dependencies
• Implementing code sharing strategies
• Setting up CI/CD for monorepos
• Versioning and publishing packages
• Debugging monorepo-specific issues

Core Concepts

1. Why Monorepos?

Advantages:

• Shared code and dependencies
• Atomic commits across projects
• Consistent tooling and standards
• Easier refactoring
• Simplified dependency management
• Better code visibility

Challenges:

• Build performance at scale
• CI/CD complexity
• Access control
• Large Git repository

2. Monorepo Tools

Package Managers:

• pnpm workspaces (recommended)
• npm workspaces
• Yarn workspaces

Build Systems:

• Turborepo (recommended for most)
• Nx (feature-rich, complex)
• Lerna (older, maintenance mode)

Turborepo Setup

Initial Setup

# Create new monorepo
npx create-turbo@latest my-monorepo
cd my-monorepo

# Structure:
# apps/
#   web/          - Next.js app
#   docs/         - Documentation site
# packages/
#   ui/           - Shared UI components
#   config/       - Shared configurations
#   tsconfig/     - Shared TypeScript configs
# turbo.json      - Turborepo configuration
# package.json    - Root package.json

Configuration

// turbo.json
{
  "$schema": "https://turbo.build/schema.json",
  "globalDependencies": ["**/.env.*local"],
  "pipeline": {
    "build": {
      "dependsOn": ["^build"],
      "outputs": ["dist/**", ".next/**", "!.next/cache/**"]
    },
    "test": {
      "dependsOn": ["build"],
      "outputs": ["coverage/**"]
    },
    "lint": {
      "outputs": []
    },
    "dev": {
      "cache": false,
      "persistent": true
    },
    "type-check": {
      "dependsOn": ["^build"],
      "outputs": []
    }
  }
}

// package.json (root)
{
  "name": "my-monorepo",
  "private": true,
  "workspaces": ["apps/*", "packages/*"],
  "scripts": {
    "build": "turbo run build",
    "dev": "turbo run dev",
    "test": "turbo run test",
    "lint": "turbo run lint",
    "format": "prettier --write \"**/*.{ts,tsx,md}\"",
    "clean": "turbo run clean && rm -rf node_modules"
  },
  "devDependencies": {
    "turbo": "^1.10.0",
    "prettier": "^3.0.0",
    "typescript": "^5.0.0"
  },
  "packageManager": "[email protected]"
}

Package Structure

// packages/ui/package.json
{
  "name": "@repo/ui",
  "version": "0.0.0",
  "private": true,
  "main": "./dist/index.js",
  "types": "./dist/index.d.ts",
  "exports": {
    ".": {
      "import": "./dist/index.js",
      "types": "./dist/index.d.ts"
    },
    "./button": {
      "import": "./dist/button.js",
      "types": "./dist/button.d.ts"
    }
  },
  "scripts": {
    "build": "tsup src/index.ts --format esm,cjs --dts",
    "dev": "tsup src/index.ts --format esm,cjs --dts --watch",
    "lint": "eslint src/",
    "type-check": "tsc --noEmit"
  },
  "devDependencies": {
    "@repo/tsconfig": "workspace:*",
    "tsup": "^7.0.0",
    "typescript": "^5.0.0"
  },
  "dependencies": {
    "react": "^18.2.0"
  }
}

pnpm Workspaces

Setup

# pnpm-workspace.yaml
packages:
  - "apps/*"
  - "packages/*"
  - "tools/*"

// .npmrc
# Hoist shared dependencies
shamefully-hoist=true

# Strict peer dependencies
auto-install-peers=true
strict-peer-dependencies=true

# Performance
store-dir=~/.pnpm-store

Dependency Management

# Install dependency in specific package
pnpm add react --filter @repo/ui
pnpm add -D typescript --filter @repo/ui

# Install workspace dependency
pnpm add @repo/ui --filter web

# Install in all packages
pnpm add -D eslint -w

# Update all dependencies
pnpm update -r

# Remove dependency
pnpm remove react --filter @repo/ui

Scripts

# Run script in specific package
pnpm --filter web dev
pnpm --filter @repo/ui build

# Run in all packages
pnpm -r build
pnpm -r test

# Run in parallel
pnpm -r --parallel dev

# Filter by pattern
pnpm --filter "@repo/*" build
pnpm --filter "...web" build  # Build web and dependencies

Nx Monorepo

Setup

# Create Nx monorepo
npx create-nx-workspace@latest my-org

# Generate applications
nx generate @nx/react:app my-app
nx generate @nx/next:app my-next-app

# Generate libraries
nx generate @nx/react:lib ui-components
nx generate @nx/js:lib utils

Configuration

// nx.json
{
  "extends": "nx/presets/npm.json",
  "$schema": "./node_modules/nx/schemas/nx-schema.json",
  "targetDefaults": {
    "build": {
      "dependsOn": ["^build"],
      "inputs": ["production", "^production"],
      "cache": true
    }