compiler-design-expert

AST-based codemods automate large-scale TypeScript and JavaScript refactors by parsing code into syntax trees, enabling safe, deterministic transformations across multiple repositories using tools like jscodeshift, Babel, or SWC.

Building custom ESLint rules leverages AST traversal to identify specific code patterns, allowing you to enforce and automate code changes at scale across JavaScript and TypeScript projects with deterministic validation.

The best way to write a codemod for a TypeScript migration is using AST tools like jscodeshift or Babel to ensure idempotent, reversible, and auditable transforms with proper testing and validation strategies.

Jscodeshift, Babel, and SWC can all be used to implement AST transforms. The Skill provides decision guidance on selecting the right tool based on your specific migration, refactor scale, and risk assessment requirements.

To ensure codemods are safe and reversible, implement idempotence guarantees, error handling, and security safeguards. Testing and validation strategies must be applied to make AST transforms deterministic and auditable.

You should avoid AST transforms when changes require complex semantic understanding beyond syntax, or when risk assessment shows potential for non-deterministic outputs. Always evaluate tool selection patterns and limitations before large-scale deployment.