jscan - JavaScript/TypeScript Code Quality Analyzer

jscan is a code quality analyzer for JavaScript/TypeScript vibe coders.

Building with Cursor, Claude, or ChatGPT? jscan performs structural analysis to keep your codebase maintainable.

Sister project: pyscn - Python Code Quality Analyzer

Features

• Complexity Analysis: Calculate McCabe cyclomatic complexity for functions
• Dead Code Detection: Find unreachable code blocks
• JavaScript Support: Full support for ES6+ JavaScript syntax
• TypeScript Support: Full parser support for TypeScript
• Fast Performance: Built in Go with tree-sitter for efficient parsing

Installation

From Source

git clone https://github.com/ludo-technologies/jscan.git
cd jscan
go build -o jscan ./cmd/jscan

Quick Install

go install github.com/ludo-technologies/jscan/cmd/jscan@latest

Usage

Analyze a file or directory

# Analyze a single file
jscan analyze src/index.js

# Analyze a directory
jscan analyze src/

# Run specific analyses
jscan analyze --select complexity src/
jscan analyze --select deadcode src/
jscan analyze --select complexity,deadcode src/

Example Output

Analyzing 1 files...

src/index.js:
  Complexity Analysis:
    calculateTotal: complexity=5, risk=medium
    processData: complexity=2, risk=low
  Dead Code Analysis:
    calculateTotal: 1 dead code blocks found
      Line 42: Code after return statement is unreachable

Analysis complete!
Files analyzed: 1

Architecture

jscan follows Clean Architecture principles:

jscan/
├── cmd/jscan/           # CLI entry point
├── domain/              # Domain models
├── internal/
│   ├── parser/         # tree-sitter JavaScript/TypeScript parser
│   ├── analyzer/       # CFG, complexity, dead code analysis
│   ├── config/         # Configuration management
│   └── reporter/       # Output formatting
└── testdata/           # Test fixtures

Development Status

Current Version: v0.1.0-alpha

jscan is in early development. Currently implemented:

• ✅ Complexity Analysis
• ✅ Dead Code Detection
• ✅ Basic CLI

Roadmap

Planned features:

• Clone Detection (APTED + LSH-based structural similarity)
• Module Analysis & Coupling Metrics
• TypeScript-specific analysis features
• Additional output formats (JSON, HTML, CSV)
• npm package distribution

Configuration

jscan uses JSON-based configuration files, following JavaScript ecosystem conventions.

Create a jscan.config.json or .jscanrc.json file in your project root:

{
  "complexity": {
    "lowThreshold": 10,
    "mediumThreshold": 20,
    "enabled": true
  },
  "deadCode": {
    "enabled": true,
    "minSeverity": "warning"
  },
  "output": {
    "format": "text",
    "showDetails": true
  }
}

See jscan.config.example.json for all available options.

Testing

# Run unit tests
go test ./...

# Test on sample files
./jscan analyze testdata/javascript/simple/

# Run with Makefile
make test
make run

License

MIT License - see LICENSE file for details

Author

Created by @daisukeyoda

Sister project: pyscn - Python Code Quality Analyzer