Package Exports

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (fallow) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

fallow

The codebase analyzer for JavaScript and TypeScript, built in Rust.

Unused code, circular dependencies, and code duplication. Found in seconds, not minutes. fallow analyzes your codebase for unused files, exports, dependencies, and types, detects circular dependencies, and finds duplicated code blocks. 3-36x faster than knip v5 (2-14x faster than knip v6), 20-33x faster than jscpd for duplication detection, with no Node.js runtime dependency.

Installation

npm install -g fallow

Usage

fallow check                     # Unused code analysis -- zero config, sub-second
fallow dupes                     # Duplication detection -- find copy-paste clones
fallow dupes --mode semantic     # Catch clones with renamed variables
fallow fix --dry-run             # Preview auto-removal of unused exports and deps

What it finds

Unused files -- not reachable from any entry point
Unused exports -- exported symbols never imported elsewhere
Unused types -- type aliases and interfaces never referenced
Unused dependencies -- packages in dependencies never imported
Unused devDependencies -- dev packages not referenced
Unused enum members -- enum values never referenced
Unused class members -- class methods and properties never referenced
Unresolved imports -- import specifiers that cannot be resolved
Unlisted dependencies -- imported packages missing from package.json
Duplicate exports -- same symbol exported from multiple modules
Circular dependencies -- import cycles in the module graph
Type-only dependencies -- production deps only used via import type

Code duplication

fallow dupes                       # Default: mild mode
fallow dupes --mode semantic       # Catch clones with renamed variables
fallow dupes --threshold 5         # Fail CI if duplication exceeds 5%
fallow dupes --save-baseline       # Save current duplication as baseline

4 detection modes (strict, mild, weak, semantic), clone family grouping with refactoring suggestions, baseline tracking, and cross-language TS/JS matching.

Framework support

84 built-in plugins covering Next.js, Nuxt, Remix, SvelteKit, Gatsby, Astro, Angular, NestJS, Vite, Webpack, Vitest, Jest, Playwright, Cypress, Storybook, ESLint, TypeScript, Tailwind, Prisma, Drizzle, Turborepo, and many more. Auto-detected from your package.json.

Configuration

Create a config file in your project root, or run fallow init:

// .fallowrc.json
{
  "$schema": "https://raw.githubusercontent.com/fallow-rs/fallow/main/schema.json",
  "entry": ["src/workers/*.ts", "scripts/*.ts"],
  "ignorePatterns": ["**/*.generated.ts"],
  "rules": {
    "unused-files": "error",
    "unused-exports": "warn",
    "unused-types": "off"
  }
}

Also supports TOML (fallow init --toml creates fallow.toml).

Documentation

License

MIT