codemod-gen_skill

Overview

This skill generates AST-based codemods to apply large-scale, safe code transformations across many files. It produces jscodeshift-compatible scripts from a plain-English description so you can refactor patterns, migrate APIs, or modernize code with confidence. No configuration required — run a single command and review the generated diff.

How this skill works

You provide a short natural-language description of the desired transformation and the tool generates a jscodeshift codemod that performs AST-aware edits. The generated codemods preserve formatting and comments, handle complex pattern changes (for example class-to-function component conversions), and can be run across entire repositories using jscodeshift or a compatible runner. The tool is intended to be used via npx and expects an environment with Node.js and an API key for the underlying model.

When to use it

• Refactoring the same pattern across hundreds of files (e.g., rename methods or replace APIs).
• Upgrading frameworks or libraries that require structural changes (e.g., React Router v5 to v6).
• Replacing deprecated APIs with modern equivalents (e.g., moment to date-fns).
• Enforcing new code patterns or project-wide style adjustments.
• Preparing large-scale automated migrations before or after a major release.

Best practices

• Run codemods on a fresh branch and keep changes isolated for review.
• Review diffs and spot-check transformed files before merging.
• Run codemods incrementally by file type or module to limit blast radius.
• Write or save the generated codemod for repeatability and CI automation.
• Add tests or run existing test suites after transformations to catch regressions.

Example use cases

• Convert React class components to functional components across the codebase.
• Replace lodash.get calls with optional chaining syntax.
• Migrate date handling from moment to date-fns with automated AST edits.
• Update import paths and API calls during a library upgrade.
• Standardize error handling patterns or logging calls across services.