jscpd

Three-part workflow to improve overall codebase health with jscpd — find and fix duplicated code, find and remove or refactor dead code, then find and simplify the largest/most complex files. Starts from --dashboard/--health to prioritize and ends by re-measuring the score.

Move code from one implementation to another function by function, tests first and code second, and check two implementations of one app for parity, with jscpd --compare as the progress measure and a coverage map binding each function to its tests. Use when porting a library or app to another language or framework (Java to Kotlin, JavaScript to Rust, a Python library to TypeScript, an iOS app to Android), when asked what is left to port, or when comparing the Android and iOS versions of an app.

Compare two folders function by function with jscpd --compare, in the same language or across languages, and explain the result. Use when asked how two codebases relate, which functions one implementation has and the other lacks, how far a port has come, whether the iOS and Android versions of an app match, or which function in one folder corresponds to a function in the other.

Guided workflow to eliminate copy-paste duplication detected by jscpd. Refactor exact, renamed and near-miss clones using extract function, parameterize, module, constant, or base class strategies, starting from the hotspots the summary ranks.

Copy-paste detector for 220+ languages. Detect exact, renamed and near-miss duplicated code, measure duplication percentages, and find refactoring hotspots with the codebase summary.