JavaScript Recipe Starter

A starter repository for learning how to create OpenRewrite recipes for JavaScript and TypeScript. This repo includes example recipes with comprehensive tests, demonstrating the full project setup you need to author and test your own recipes.

Getting started

New to OpenRewrite JavaScript recipe development? Start by checking out the OpenRewrite documentation and our JavaScript LST examples doc.

Quick start

Clone this repository and install dependencies:

git clone git@github.com:moderneinc/javascript-recipe-starter.git
cd javascript-recipe-starter
npm install

Run the tests:

npm test

Example recipes

This repository includes example recipes that demonstrate different authoring approaches and OpenRewrite capabilities:

Transformation recipes

• MigrateUtilFunctions - Replaces deprecated Node.js util type checking methods (like util.isArray()) with native JavaScript equivalents (like Array.isArray()). Demonstrates pattern-based, declarative recipe authoring using pattern and rewrite() rules with type context.

• SayHelloRecipe - Adds a hello() method to JavaScript/TypeScript classes that don't already have one. Demonstrates visitor-based recipe authoring with manual LST manipulation and the template API.

• SemanticForwardRefMigration - Wraps React forwardRef() calls with memo() for better performance. Demonstrates semantic type matching that works across different import styles (named, namespace, default, and aliased imports). Shows how one pattern with type context can match syntactically different but semantically equivalent code.

Search recipes

• FindMethodCalls - Finds and records all calls to a specified method name in a data table. Demonstrates search recipes that collect findings without modifying code, useful for impact analysis before migrations. Shows the @Option decorator for configurable recipes and @Column for data table structure. Results can be exported to CSV.

Project structure

javascript-recipe-starter/
├── src/
│   ├── migrate-util-functions.ts
│   ├── say-hello-recipe.ts
│   ├── semantic-matching.ts
│   ├── find-method-calls.ts
│   └── index.ts
├── test/
│   ├── migrate-util-functions.test.ts
│   ├── say-hello-recipe.test.ts
│   ├── semantic-matching.test.ts
│   └── find-method-calls.test.ts
├── package.json
├── tsconfig.json
└── jest.config.js

Running your recipes

To run these recipes against your own JavaScript/TypeScript codebase, you'll need to use the Moderne CLI and configure it to use JavaScript LSTs:

mod run . --recipe=MigrateUtilFunctions

License

See LICENSE file for details.