🔁 CDK Imports Swap

Optimize AWS CDK CloudFormation templates by replacing redundant ExportsOutputFn imports with named exports.

This utility analyzes your synthesized CDK templates from the cdk.out directory, identifies where the same exported values are referenced under both ExportsOutputFn* and named exports, and rewrites the templates to use named exports for better readability and consistency.

✨ Features

• 🔍 Scans all *.template.json files inside cdk.out/assembly-*
• 📦 Detects ExportsOutputFn* style exports
• 🏷 Identifies equivalent named exports across templates
• 🔁 Replaces Fn::ImportValue references using ExportsOutputFn* with named alternatives
• 🧼 Cleans up cross-stack references and improves maintainability

📦 Installation & Usage

Prerequisites

• Node.js (v14+ recommended)
• TypeScript
• CDK project with cdk.out folder (run cdk synth first)

Run the Script

npx cdk-imports-swap.ts

You may also add this as an npm/yarn script inside your project for convenience.

📁 Example

Before optimization:

"Fn::ImportValue": "ExportsOutputFn12345"

After optimization:

"Fn::ImportValue": "SharedVpcId"

🛠 How It Works

1. Loads all templates from cdk.out/assembly-*/*.template.json
2. Identifies Outputs with Export keys, separating ExportsOutputFn* from named exports
3. Compares values of both export types
4. Finds and replaces matching imports using a named export instead of ExportsOutputFn
5. Saves modified template files in place

🔒 Safety

• Only modifies files inside the cdk.out directory
• Uses deep value comparison to ensure safe replacements
• Outputs logs for every match and modification

🧪 Development

To run locally:

git clone https://github.com/your-org/cdk-imports-swap.git
cd cdk-imports-swap
npm install
npx ts-node src/cdk-imports-swap.ts

📄 License

MIT © Iurii Favi

🤝 Contributing

Pull requests and suggestions are welcome! Please open an issue first to discuss what you would like to change.