Jscpd

jscpd

Copy-paste detector for programming source code, supports 150+ languages. Use this skill to run jscpd and understand its output.

Quick Start

# Run with ai reporter (compact output optimized for agents)
npx jscpd --reporters ai 

# With ignore patterns
npx jscpd --reporters ai --ignore "**/node_modules/**,**/dist/**" 

# Scope to specific formats
npx jscpd --reporters ai --format "javascript,typescript" 

AI Reporter Output Format

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:

• Same file: path/file.ts 10-25 ~ 45-60 (shared path shown once)
• Same directory: shared/prefix/ file-a.ts:10-25 ~ file-b.ts:42-57 (common prefix factored out)
• Different paths: path/a.ts:10-25 ~ path/b.ts:42-57

Options

| Option | Description | |--------|-------------| | --reporters ai | Use the AI-optimized reporter (compact clone list for agents) | | --reporters html | Generate HTML report | | --reporters json | Output JSON report | | --min-tokens N | Minimum tokens to consider a duplication (default: 50) | | --min-lines N | Minimum lines to consider a duplication (default: 5) | | --min-similarity N | Minimum similarity percentage (default: 100, range: 1-100) | | --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 | | --output "path" | Directory to write reports to | | --silent | Suppress output (useful with --output only) | | --list-output | Print clone list to stdout (alternative to ai reporter) | | --store-path "path" | Directory for LevelDB cache | | --no-tips | Disable tips in output (enabled by default in CI) | | --config "path" | Path to .jscpd.json config file |

Configuration File

Create a .jscpd.json in your project root:

{
  "threshold": 0,
  "reporters": ["ai"],
  "ignore": ["**/node_modules/**", "**/dist/**", "**/*.min.*"],
  "format": ["typescript", "javascript"],
  "minLines": 5,
  "minTokens": 50,
  "output": "./reports/jscpd"
}

Refactoring Duplicated Code

Once you've detected clones, use the dry-refactoring skill for a guided workflow to eliminate them:

→ dry-refactoring — step-by-step refactoring strategies and workflow for removing duplication. Install with: ``bash npx skills add https://github.com/kucherenko/jscpd --skill dry-refactoring ``

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: vahidkaargar
• Source: vahidkaargar/it-department-skills
• License: MIT

Install and usage instructions live in the source repository linked above.