jscpd vs QuickDup

jscpd is a free, open-source tool for finding repeated code in repositories. It can fail a build when duplication exceeds a configured threshold, making it usable in local development and CI. The project says it supports 224 languages. Exact clones are detected by default, while renamed, near-miss, and semantic clone checks are optional; semantic detection is experimental.

Version 5 is available as a self-contained native binary that does not need Node.js, with direct macOS, Linux, and Windows binaries for x64 and ARM64. Reports include HTML, JSON, XML, README badges, SARIF, CodeClimate, and OpenMetrics. The GitHub Action can enforce a threshold and upload SARIF for GitHub Code Scanning, and GitLab CI reporters are documented. Developers can also use pre-commit hooks or Docker. A dashboard summarizes project size, duplication, complexity, dead code, and a health score. Dead-code analysis covers JavaScript, TypeScript, and Python, plus Rust when compiler diagnostics are supplied.

QuickDup is a repository code clone detector that finds candidate duplicate patterns using changes in indentation and the first word on each line. It skips comments and blank lines, tokenizes source lines and uses Jaccard similarity to filter patterns below a default 75% threshold. It does not parse abstract syntax trees. Detection options include normalized-indent, word-indent, word-only and inlineable strategies. The README lists comment-prefix detection for languages including Go, C and C++, Java, JavaScript and TypeScript, C#, Python, Ruby, SQL, Lua and MATLAB. QuickDup can emit GitHub Actions annotations for inline pull request comments and restrict them to files changed against a Git reference. Results are written as machine-readable JSON in a .quickdup directory. Incremental caching is available only for the word-indent strategy; other listed strategies re-parse files on each run. The README reports processing about 100,000 lines in about 500 ms on 8 cores. QuickDup is free under the MIT License, with installers for Linux, macOS and Windows, or installation from source with Go.