Refactor Strategy with AI

Plan a big refactor as ordered, behavior-preserving steps; gate each with tests.

Docs & RefactorAdvanced

Why

GitHub's 2024 survey found 81% of developers expect AI tools to become more integrated in documenting code over the next year, the highest of any workflow. Big refactors fail when done in one pass.

AI can decompose into ordered steps where each preserves behavior (gated by existing tests), making the whole thing bisectable and revertible.

When

Use for refactors touching >10 files or crossing module boundaries. Skip for local renames.

How

1. State the goal + invariants (behavior unchanged). 2. Ask: "ordered steps; each preserves behavior; each runnable + tested independently". 3. Review the order; fix dependencies between steps. 4. Execute one step per commit; run tests after each. 5. Red test → revert that step and re-plan.

Example

Goal: replace assertValid with zod across 40 routes. Plan: (1) add zod schemas alongside; (2) swap one route per commit; (3) remove assertValid last. Each step: tsc + tests green. Red on step 2 → revert that route, re-plan.

Common Problems

⚠Error: Cannot find module 'xxx' after refactor → re-run `npm install` and `npx tsc --noEmit`; refactors often drop or rename imports.
⚠Error: "Cannot read properties of undefined" after refactor → run the test suite (`npm test`) to catch behavior changes; refactor must be behavior-preserving.
⚠Error: Docs drift: example no longer runs → execute examples in CI (`npm run docs:check`); tested examples never drift.

Best Practices

✓Decompose into independently-testable, behavior-preserving steps.
✓Commit per step so you can bisect and revert.
✓Measure the outcome with a concrete metric (time saved, defect rate, test coverage) so the practice can be justified and improved.

FAQ

What is Refactor Strategy with AI?

Plan a big refactor as ordered, behavior-preserving steps; gate each with tests. It helps developers quickly grasp the core value and use cases of Refactor Strategy with AI.

How do I get started with Refactor Strategy with AI?

To get started with Refactor Strategy with AI, focus on these points first: State the goal + invariants (behavior unchanged).

What are common mistakes with Refactor Strategy with AI?

Common mistakes when using Refactor Strategy with AI include: Error: Cannot find module 'xxx' after refactor → re-run `npm install` and `npx tsc --noEmit`; refactors often drop or rename imports.; Error: "Cannot read properties of undefined" after refactor → run the test suite (`npm test`) to catch behavior changes; refactor must be behavior-preserving.; Error: Docs drift: example no longer runs → execute examples in CI (`npm run docs:check`); tested examples never drift..

What are the best practices for Refactor Strategy with AI?

Best practices for Refactor Strategy with AI include: Decompose into independently-testable, behavior-preserving steps.; Commit per step so you can bisect and revert.; Measure the outcome with a concrete metric (time saved, defect rate, test coverage) so the practice can be justified and improved..

How do I learn more about Refactor Strategy with AI?

Start with the official docs, then search real-world examples on GitHub. Validate patterns in a small scratch repo before applying them to production code.