Computer, refactor my code!
summary
Demonstrates writing codemods that parse JavaScript into an AST, traverse and transform nodes, then regenerate code; one example runs over 300 automated edits in a real codebase and another rewrites a chained SDK API across ~30 apps into single-object calls. Uses jscodeshift, built on recast, and debugs transforms with AST Explorer. Typical nontrivial transform takes a few hours to reach 90% correctness; replacements are deterministic and preserve nested function arguments.
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chapters (11)
- 0:00Introduction to code refactoring
- 3:03Case study and motivation
- 9:59Understanding AST basics
- 15:24Introducing code mods
- 17:33Tools for AST traversal
- 22:57Building your first transform
- 24:47Demo: Simple identifier replacement
- 28:05Demo: Targeted node replacement
- 33:47Demo: Complex AST construction
- 39:18Summary and encouragement
- 40:02Q&A session
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