Keeping the codebase readable as it grows

The problem

Code written fast is written twice. Duplicated helpers, functions that grew past anyone’s attention and tests that were never added are not bugs, so nothing flags them, and they are what makes the next change slow.

What visualdiff does

• Déjà vu finds new helpers that already exist under another name, and bodies copied from elsewhere in the change.
• Complexity, error handling, test and hygiene rules run over every line, with a severity that fits what the repository is.
• A prototype can be read with its maintainability rules off, so the noise is gone where it does not belong and present where it does.