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PKG002-missing-types

Dimension: packaging Default severity: Low Languages: JavaScript / TypeScript (npm) Kind: ProjectLevel CWE: (none) OWASP: —

What it detects​

Fires when an npm package provides no TypeScript type declarations — specifically when all of the following are true:

  1. package.json has no types or typings field.
  2. No .d.ts file exists adjacent to the entry point.

Entry point heuristic: the main field in package.json is used as the entry point; if main is absent, index.js is assumed. The companion .d.ts is checked by swapping the file extension.

Why it matters​

A package with no type declarations provides no type information to TypeScript consumers. This causes noImplicitAny errors in strict codebases and worsens the developer experience for all TypeScript users.

Example — flagged​

{
  "name": "my-lib",
  "main": "dist/index.js"
}

No types field and no dist/index.d.ts file present.

Example — not flagged​

{
  "name": "my-lib",
  "main": "dist/index.js",
  "types": "dist/index.d.ts"
}

Or: package.json has no types field but dist/index.d.ts exists on disk.

How to fix​

Option 1 — generate declarations from TypeScript source:

Add "declaration": true to tsconfig.json and set the types field in package.json:

{
  "types": "dist/index.d.ts"
}

Option 2 — hand-author a declaration file:

Create index.d.ts (or dist/index.d.ts) and declare your public API.

Option 3 — use @types package:

If you maintain a companion @types/my-lib package, reference it in your README.md but add a types field pointing to the stub:

{
  "types": "./index.d.ts"
}

Suppression​

[ignore]
rules = ["PKG002-missing-types"]

References​