madge-deps

Madge analyzes JavaScript module graphs (AMD, CommonJS, ES6) and CSS preprocessor imports (Sass, Stylus, Less) per the Madge README. NPM deps and Node core modules are excluded by default.

When to use

• A bundle that compiles but throws Cannot read property X of undefined at runtime - likely a circular import causing partial module init.
• Pre-merge gate to block any new circular dep.
• Finding orphan files (no imports + no exports referenced) to delete.

Step 1 - Install

npm install -g madge
# or per-project
npm install -D madge

Optional Graphviz for visual graphs:

Per the Madge README.

Step 2 - Detect circular dependencies

# Single entry point
madge --circular src/index.ts

# Whole directory
madge --circular src/

Exit code: 0 if none found, 1 if any circular path exists. Use directly in CI.

Step 3 - Find orphans + leaves

# Files imported by nothing
madge --orphans src/

# Files that import nothing (terminal modules)
madge --leaves src/

Orphans are deletion candidates; verify usage outside source tree (scripts, configs, side-effect imports) before removal.

Step 4 - Visualize

# Render full graph as SVG (requires Graphviz)
madge --image graph.svg src/

# Show what depends on a specific file
madge --depends src/config/db.ts src/

# Export raw DOT for custom rendering
madge --dot src/ > graph.gv

Step 5 - Configure for production-only scope

.madgerc in project root:

{
  "fileExtensions": ["ts", "tsx", "js", "jsx"],
  "excludeRegExp": [
    "\\.test\\.(ts|tsx|js|jsx)$",
    "\\.spec\\.(ts|tsx|js|jsx)$",
    "__tests__/",
    "__mocks__/",
    "node_modules/",
    "dist/",
    "build/"
  ],
  "tsConfig": "tsconfig.json"
}

Test files are excluded so tests can intentionally import production modules without flagging the production tree.

Step 6 - CI gate

# GitHub Actions
- name: Block circular deps
  run: npx madge --circular --extensions ts,tsx src/

- name: Detect new orphans (advisory)
  run: npx madge --orphans --extensions ts,tsx src/ || true

The first step fails on any circular path; the second is informational only (orphans require human judgment - could be webpack entry, dynamic import, etc.).

Anti-patterns

Limitations

• Madge resolves static imports only; dynamic import() calls and require() with computed strings are not in the graph.
• ESM-only projects: ensure Madge version supports your Node ESM resolver. Check the Madge README for current ESM compat notes.

References

• Madge README - CLI flags, .madgerc schema, extension support