safe-extraction

To split monolith files safely, you preserve existing public API import paths via explicit barrel re-exports. This approach ensures downstream consumer code resolves imports correctly without requiring manual updates across the codebase.

Test mocks break during code extraction when dependency injection seams are not preserved. Maintaining test mockability requires implementing getter/setter proxy patterns, such as an _internals proxy, to keep test mocking functional across the newly separated submodules.

When relocating code between modules, CI path allowlists must be updated to recognize the new submodule locations. Automating these CI quality gate updates prevents invariant check failures and ensures the continuous integration build passes.

The best way to refactor oversized TypeScript files without test regressions is to validate full cross-file test compatibility post-extraction. This involves verifying that dependency injection seams and barrel exports function identically before and after the split.

Proper code extraction does not alter runtime behavior when splitting large monolith files. By preserving public APIs via barrel re-exports and maintaining dependency injection seams, the refactoring process safely relocates code without changing execution logic.