JoshuaKGoldberg/TypeStat

Health v2 · maintenance only

Adoption not part of the score

2254 stars · 46 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

TypeStat is a CLI utility that converts JavaScript files to TypeScript and improves type annotations in existing TypeScript code. It applies automated type mutations that only add or remove types without changing runtime behavior.

Use cases

• convert a JavaScript codebase to TypeScript
• add types to files freshly converted from JavaScript
• fix noImplicitAny and noImplicitThis violations
• annotate missing nulls and undefineds for strictNullChecks
• automatically improve type annotations in existing TypeScript projects

When to choose

• you are migrating a JavaScript project to TypeScript incrementally
• you want to enable stricter compiler flags like strictNullChecks without manually annotating everything
• you need automated, behavior-preserving type fixes across many files

When to avoid

• you want a one-time full rewrite with runtime refactoring rather than type-only mutations
• your project is already fully and strictly typed
• you need a linter or formatter rather than a type mutation tool

Facets

cli-tool · maturity active

cli parser developer-tools type-system developer-tools programming-languages cli cross-platform typescript javascript-to-typescript code-mutation static-analysis codemod type-annotation strict-null-checks no-implicit-any automation nodejs

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