Introducing the new Codemod CLI

We’re excited to announce the launch of the new Codemod CLI; your all-in-one toolkit for automating large-scale code transformations, refactors, and migrations. Whether you’re wrangling a monorepo, modernizing legacy code, or rolling out sweeping changes across dozens of projects, Codemod CLI brings power, safety, and flexibility to your workflow.

What’s new?

• First-class workflow authoring: Compose, validate, and run workflows with a single tool.
• Self-hostable & portable: No server required. Run anywhere you have a shell.
• Schema-validated shared state: Safely coordinate complex, multi-step migrations.
• Parallel & resumable: Run tasks in parallel, pause for manual approval, and resume after interruptions.

Quick Start: Your First Codemod Workflow

#1 Create a New Workflow Project

Codemod CLI supports three workflow types:

• Shell command workflow codemod: Automate any shell command or script.
• JavaScript ast-grep codemod: Use jssg (JavaScript ast-grep) for fast, pattern-based code transformations.
• YAML ast-grep codemod: Use YAML-based rules for language-agnostic AST transformations.

To create a new project, run:

npx codemod init

You’ll be prompted to choose your workflow type, project name, and other details. This sets up a ready-to-go project structure, including:

my-codemod/
├── codemod.yaml        # Project metadata
├── workflow.yaml       # Workflow definition
├── rules/              # ast-grep rules
├── jssg/               # jssg codemods
├── scripts/            # Custom scripts (for shell scripts)
└── tests/              # Test fixtures

#2 Build Your Transform with Codemod Studio

For ast-grep YAML and jssg codemods, Codemod Studio is your visual playground for building, testing, and refining code transformations.

1. Open ** Codemod Studio ** in your browser.
2. Select your language and codemod type (ast-grep YAML or jssg).
3. Write and test your transformation rules interactively.
4. Once satisfied, copy your rule.
5. Paste your rule into ** rules/config.yml ** (for YAML) or ** jssg/codemod.ts ** (for jssg).

#3 Run Your Workflow with Codemod CLI

With your workflow and rules in place, you’re ready to validate and execute your codemod:

# Validate your workflow for errors
npx codemod workflow validate -w ./example-codemod/workflow.yaml # Replace with actual path
 
# Run the workflow locally
npx codemod workflow run -w ./example-codemod/workflow.yaml # Replace with actual path

Next steps

• Explore the Codemod CLI docs to learn more.
• For pro workflows and enterprise migrations, book us .