Extra Conditions Example

This example demonstrates how to use the extraConditions option in package.json validation to allow custom export conditions.

Configuration

// packem.config.ts
import { defineConfig } from '@visulima/packem/config'
import transformer from '@visulima/packem/transformer/esbuild'

export default defineConfig({
    transformer,
    entries: [
        {
            input: "src/index.ts",
        },
    ],
    validation: {
        packageJson: {
            extraConditions: ["custom-bundler", "my-framework", "special-env"]
        }
    }
})

Package.json Example

{
    "name": "my-package",
    "exports": {
        ".": {
            "custom-bundler": "./dist/custom.js",
            "my-framework": "./dist/framework.js",
            "special-env": "./dist/special.js",
            "import": "./dist/index.mjs",
            "require": "./dist/index.cjs",
            "default": "./dist/index.js"
        }
    }
}

What this does

• Without extraConditions: Packem would warn about unknown conditions custom-bundler, my-framework, and special-env
• With extraConditions: These custom conditions are recognized as valid and no warnings are generated
• Unknown conditions not listed in extraConditions will still generate warnings

Use Cases

• Custom bundler-specific conditions
• Framework-specific export conditions
• Environment-specific conditions
• Tool-specific conditions
• Any custom export condition your package needs to support

Standard Conditions

Packem already recognizes these standard and community conditions without needing to add them to extraConditions:

Standard Node.js Conditions

• import - ES modules
• require - CommonJS
• node - Node.js environment
• default - Fallback condition

Community Conditions

• browser - Browser environment
• development - Development builds
• production - Production builds
• types - TypeScript declarations
• react-native - React Native platform
• react-server - React Server Components
• edge-light - Edge runtime environments

Related Examples

• Package.json Validation - Complete package.json validation setup
• Bundle Size Limits - Configure bundle size validation
• Multi-Runtime Exports - Target multiple runtimes with conditional exports