create-new-package-in-monorepo

Create New Package

Create a new buildable TypeScript package in the Packmind monorepo using Nx tools and configure it for use across applications.

When to Use

• Creating a new shared library package for common utilities or domain logic
• Setting up a domain-specific package following DDD architecture
• Establishing internal dependencies for code reuse across apps and packages
• Extracting common code into a reusable module

Context Validation Checkpoints

• What is the package name and its primary responsibility?
• Which packages or applications will consume this package?
• Will the package be used by the API application (requires webpack config)?
• What external dependencies does the package require (e.g., TypeORM, Winston)?
• Are there any special build requirements (e.g., WASM files, assets)?

Recipe Steps

Step 1: Generate Package Scaffold with Nx

Run the Nx generator to create the package structure with TypeScript configs, Jest setup, ESLint config, and project.json.

nx generate @nx/js:library <package-name> \
  --directory=packages/<package-name> \
  --buildable \
  --publishable=false \
  --unitTestRunner=jest

Step 2: Configure Package Metadata

Update packages/<package-name>/package.json with the correct name and dependencies. Always use @packmind/ prefix and set "private": true for internal packages.

{
  "name": "@packmind/<package-name>",
  "version": "0.0.1",
  "private": true,
  "type": "commonjs",
  "main": "./src/index.js",
  "types": "./src/index.d.ts",
  "dependencies": {
    "tslib": "^2.3.0"
  }
}

Step 3: Update TypeScript Path Mappings

Add the path alias to tsconfig.base.json (Nx generates it without @packmind/ prefix - fix this). Then regenerate the effective TypeScript config by running node scripts/select-tsconfig.mjs.

{
  "compilerOptions": {
    "paths": {
      "@packmind/<package-name>": ["packages/<package-name>/src/index.ts"]
    }
  }
}