// Detect and eliminate copy-paste duplication in source code using jscpd with the AI reporter.
| name | jscpd |
| description | Detect and eliminate copy-paste duplication in source code using jscpd with the AI reporter. |
Copy-paste detector for programming source code, supports 150+ languages. Use this skill to find duplicated code and refactor it away.
# Run with ai reporter (compact output optimized for agents)
npx jscpd --reporters ai <path>
# With ignore patterns
npx jscpd --reporters ai --ignore "**/node_modules/**,**/dist/**" <path>
# Scope to specific formats
npx jscpd --reporters ai --format "javascript,typescript" <path>
The ai reporter produces compact, token-efficient output designed for agent consumption:
Clones:
src/ foo.ts:10-25 ~ bar.ts:42-57
src/utils/helpers.ts:100-120 ~ src/utils/other.ts:5-25
---
3 clones · 4.2% duplication
Each line represents one clone pair:
path/file.ts 10-25 ~ 45-60 (shared path shown once)shared/prefix/ file-a.ts:10-25 ~ file-b.ts:42-57 (common prefix factored out)path/a.ts:10-25 ~ path/b.ts:42-57| Option | Description |
|---|---|
--reporters ai | Use the AI-optimized reporter (required for this skill) |
--min-tokens N | Minimum tokens to consider a duplication (default: 50) |
--min-lines N | Minimum lines to consider a duplication (default: 5) |
--threshold N | Exit with error if duplication % exceeds N |
--ignore "glob" | Ignore patterns (comma-separated) |
--format "list" | Limit to specific languages (e.g. typescript,javascript) |
--pattern "glob" | Glob pattern to select files |
--gitignore | Respect .gitignore |
--silent | Suppress output (useful with --output only) |
--reporters ai on the target pathExtract function — when the duplicate is a block of logic:
// Before: same block in two places
// After: shared function called from both places
Extract module/utility — when the duplicate spans multiple files in different domains:
// Move shared logic to a shared utility file and import it
Extract constant or config — when the duplicate is repeated data or configuration.
Template/base class — when the duplicate is structural (e.g., repeated class shape).
Always ensure:
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