dead-deps-gauge

Find dependencies you declare but never use, and imports that are missing from package.json.

dead-deps-gauge reads every JavaScript and TypeScript file in a package, works out which packages each one imports, and compares that with package.json. Code that imports something not in package.json (and only works through hoisting), production code that needs a package listed only under devDependencies, and dependencies nothing uses all fail the build, each with the file and line and the exact command to fix it.

CLI, library and GitHub Action. Node.js 18+, zero runtime dependencies. By Louis Wright.

Features

Import extraction without a parser: import/export … from, import type, side-effect imports, require, require.resolve, dynamic import(), TypeScript import x = require(), jest.mock/vi.mock, and /// <reference types> headers. A lexer skips comments, and template literals and strings that hold code samples.
More than imports: binaries run from package.json scripts (resolved through each dependency's bin, or a table of well-known tools), ESLint/Babel/Prettier/Jest/commitlint/stylelint/TypeScript config files and their short plugin names, tsconfig types/extends/importHelpers, @types/* paired with the package they type, and tools implied by config files (tsconfig.json → typescript, .husky/ → husky…).
Production vs development: tests, fixtures, scripts, examples, stories and *.config.* files are dev-only. If package.json has "files", anything that isn't published is dev-only too. install/postinstall scripts of published packages count as production.
Monorepos: nested packages are skipped. A workspace root's devDependencies satisfy dev imports inside packages, but production imports must still be declared locally, which catches "works only because it's hoisted" bugs.
Output: text, JSON, SARIF 2.1.0 and Markdown; --fail-on; exit codes 0/1/2; allowlist entries with expiry dates.

Rules

Rule	Default severity	What it catches
`missing-dependency`	high	Imported by production code but not declared in package.json
`dev-dependency-in-production`	high	Imported by production code but only declared in devDependencies
`unused-dependency`	medium	Declared in dependencies but never used
`missing-dev-dependency`	medium	Imported by tests/tooling but not declared
`duplicate-declaration`	medium	Declared in both dependencies and devDependencies
`unused-dev-dependency`	low	Declared in devDependencies but never used
`builtin-shadowed`	low	Dependency has the same name as a Node.js built-in module
`types-in-dependencies`	low	@types/* in dependencies of a package that ships no types
`unused-optional-dependency`	info	Declared in optionalDependencies but never used
`allowlist-expired`	medium	Allowlist entry has expired
`allowlist-unused`	info	Allowlist entry matched nothing

Install and run

npx dead-deps-gauge                              # scan the current package
npx dead-deps-gauge packages/api --fail-on medium
npx dead-deps-gauge --ignore "generated/**" --ignore-deps "@company/runtime-*"
npx dead-deps-gauge -f json > deps-report.json

Sample output

dead-deps-gauge — fixture-app@1.0.0
6 file(s) scanned; 6 dependencies, 9 devDependencies

HIGH     src/index.js:5 "debug" is used by production code (src/index.js:5) but is only a devDependency [dev-dependency-in-production]
         ↳ fix: Move it to "dependencies" (npm install debug --save-prod), or mark the file as dev-only with "devPaths".
HIGH     src/index.js:7 "dotenv" is used by src/index.js:7 but is not in package.json [missing-dependency]
         ↳ fix: npm install dotenv  (it only works today through hoisting or a transitive install)
MEDIUM   package.json "left-pad" is in dependencies but nothing imports or runs it [unused-dependency]
         ↳ fix: npm uninstall left-pad  (or allowlist it with a reason if it is loaded indirectly)
LOW      package.json "fs" has the same name as the Node.js built-in "fs"; imports resolve to the built-in [builtin-shadowed]
         ↳ fix: Remove it and use "node:fs".

Options

dead-deps-gauge 1.0.0 — find unused dependencies and imports missing from package.json

Usage: dead-deps-gauge [dir] [options]

Scan
      --ignore <globs>       Paths to skip (comma-separated or repeated), e.g. "generated/**"
      --ignore-deps <globs>  Dependencies never to report, e.g. "@company/runtime-*"
      --dev-paths <globs>    Extra globs treated as dev-only (tests, tooling); defaults include test/, scripts/, *.test.*, *.config.*

Common
  -c, --config <file>     JSON config (default: .dead-deps-gauge.json or "deadDepsGauge" in package.json)
  -f, --format <fmt>      text (default) | json | sarif | markdown
      --json <file>       Also write a JSON report
      --sarif <file>      Also write SARIF 2.1.0
      --markdown <file>   Also write Markdown (e.g. for a job summary)
      --fail-on <sev>     critical | high | medium | low | info | none (default: high)
      --list-rules        Print rules and default severities
      --no-fixes          Hide fix suggestions in text output
      --no-color          Disable colours
  -v, --version / -h, --help

Exit codes: 0 = passed, 1 = findings at or above --fail-on, 2 = usage, config or read error.

Some packages are loaded by name at runtime (template engines, framework plugins, reflect-metadata). List them in ignoreDeps, or allowlist them with a reason so the exception is documented.

Configuration and allowlist

Options can live in .dead-deps-gauge.json (or a "deadDepsGauge" key in package.json, or --config <file>):

{
  "failOn": "medium",
  "severity": { "unused-dev-dependency": "low" },
  "allowlist": [
    { "rule": "unused-dependency", "subject": "reflect-metadata", "reason": "Loaded by the framework at runtime", "expires": "2027-03-31" }
  ],
  "ignoreDeps": ["@company/runtime-*"],
  "ignore": ["generated/**"],
  "devPaths": ["tools/**"]
}

severity changes a rule's severity, or turns it "off".
allowlist entries suppress matching findings. Each needs a reason and matches on any combination of rule, file, subject (globs with *) and match (a substring of the message). Add expires (YYYY-MM-DD) so the exception is time-boxed: once it lapses the finding comes back along with an allowlist-expired finding (medium). Entries that no longer match anything are reported as allowlist-unused (info).

prodPaths (globs) forces files to count as production even if they match a dev pattern.

Output and exit codes

--format text (default), json, sarif (SARIF 2.1.0 for GitHub code scanning) or markdown (for job summaries and PR comments). --json, --sarif and --markdown write extra report files in the same run.
--fail-on <severity> sets the threshold (critical, high, medium, low, info, none; default high).
Exit codes: 0 passed, 1 findings at or above --fail-on, 2 usage, config or read error.

GitHub Action

permissions:
  contents: read
  security-events: write   # only needed for the SARIF upload
jobs:
  dead-deps-gauge:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
        with: { persist-credentials: false }
      - uses: MrLouisWright/dead-deps-gauge@v1
        with:
          fail-on: high
          sarif: dead-deps-gauge.sarif
      - uses: github/codeql-action/upload-sarif@v3
        if: always()
        with: { sarif_file: dead-deps-gauge.sarif }

Input	Description	Default
`path`	Project directory	`.`
`ignore`	Comma-separated path globs to skip	``
`fail-on`	Failure threshold	`high`
`config`	Config file path
`sarif` / `json`	Write SARIF / JSON report to this path
`job-summary`	Add the Markdown report to the job summary	`true`
`args`	Extra CLI arguments

The action runs the bundled CLI with Node 20; it has no dependencies to install. Pin it to a commit SHA if your policy requires it.

Library

import { check, extractImports, packageName } from 'dead-deps-gauge';
const report = check('.', { ignoreDeps: ['reflect-metadata'] });
extractImports("import x from 'lodash/fp'"); // [{ spec: 'lodash/fp', line: 1, typeOnly: false }]
packageName('lodash/fp');                    // 'lodash'

Types are included.

Requirements

Node.js 18 or newer. Zero runtime dependencies.

Support

If this project is useful to you, you can support its development with a donation: Buy me a coffee. It helps keep these tools maintained, documented and free for everyone.

Credit (optional)

Free to use under MIT, no attribution required. If dead-deps-gauge helps you, a link back is appreciated:

<a href="https://louiswright.co.uk">Built with dead-deps-gauge by Louis Wright</a>

[![Built with dead-deps-gauge by Louis Wright](https://img.shields.io/badge/built%20with-dead--deps--gauge-blue)](https://louiswright.co.uk)

Licence

Framework plugins, aliases and `--fix`

Frameworks load packages that no import mentions. Built-in plugins understand them, so they are not reported as unused:

Plugin	What it reads
next	`next` implies `react` and `react-dom`
jsx	`.jsx`/`.tsx` files use `react`, `preact` or `solid-js` through the automatic JSX runtime
vite	`vite.config.` / `vitest.config.`: `environment: 'jsdom' \| 'happy-dom'`, `coverage.provider`, browser mode
jest	`jest.config.*` or `"jest"` in package.json: `testEnvironment`, `preset`, `transform`
eslint	`eslint.config.*` flat-config packages
storybook	`.storybook/main.*` `addons` and `framework`
postcss	`postcss.config.*` plugin objects (`{ autoprefixer: {} }`)

Disable with --no-plugins, or choose with "plugins": ["next", "jest"] in the config.

Imports matching tsconfig/jsconfig compilerOptions.paths (including through extends) and #subpath imports are not packages. In a workspace, a missing sibling package gets a workspace:* fix.

npx dead-deps-gauge --fix --dry-run   # show what would be removed
npx dead-deps-gauge --fix             # remove unused (dev/optional) dependencies from package.json

Module formats and types

Ships ESM (import) and a bundled CommonJS build (require), with TypeScript declarations generated from the source:

import * as lib from 'dead-deps-gauge';      // ESM
const lib = require('dead-deps-gauge');      // CommonJS

Tests live in test/ and run on Node 18, 20 and 22 in GitHub Actions, including a require+import check. Releases are published with npm publish --provenance.

dead-deps-gauge

dead-deps-gauge

Features

Rules

Install and run

Sample output

Options

Configuration and allowlist

Output and exit codes

GitHub Action

Library

Requirements

Support

Credit (optional)

Licence

Framework plugins, aliases and --fix

Module formats and types

Framework plugins, aliases and `--fix`