# @tsd/typescript

> TypeScript with some extras for type-checking.

Latest version **6.0.3** (published 2026-04-17) · MIT license · 0 weekly downloads

## Install

```sh
npm install @tsd/typescript
pnpm add @tsd/typescript
yarn add @tsd/typescript
bun add @tsd/typescript
```

## Health

**Score 65/100 (B)** — status: active.

Positive: has types; no vulnerabilities; has provenance; high maintenance score; high quality score.

Warnings: low downloads; no esm support; large bundle.

## Facts

| | |
|---|---|
| Version | 6.0.3 |
| Published | 2026-04-17 |
| First published | 2021-05-13 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | CommonJS |
| Node | >=14.17 |
| Dependencies | 0 |
| Unpacked size | 37 MB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| GitHub stars | 28 |
| Author | Sam Verschueren |
| Maintainers | samverschueren |
| Keywords | tsd, typescript, typecheck |

## Links

- npm: https://www.npmjs.com/package/@tsd/typescript
- Repository: https://github.com/tsdjs/typescript
- Homepage: https://github.com/tsdjs/typescript#readme
- Issues: https://github.com/tsdjs/typescript/issues
- npm.io page: https://npm.io/package/@tsd/typescript

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## Recent versions

- 6.0.3 (latest) — 2026-04-17
- 6.0.2 — 2026-03-25
- 5.9.3 — 2025-10-01
- 5.9.2 — 2025-08-05
- 5.8.3 — 2025-04-05
- 5.8.2 — 2025-02-28
- 5.7.3 — 2025-01-09
- 5.7.2 — 2024-11-22
- 5.6.3 — 2024-10-09
- 5.6.2 — 2024-09-09
- 5.5.4 — 2024-07-23
- 5.5.3 — 2024-07-02
- 5.5.2 — 2024-06-20
- 5.4.5 — 2024-04-10
- 5.4.4 — 2024-04-04
- … 42 more at https://npm.io/package/@tsd/typescript/versions

## README

# @tsd/typescript ![CI](https://github.com/tsdjs/typescript/workflows/CI/badge.svg)

> TypeScript with some extras for type-checking.

This is a drop-in replacement for [TypeScript](https://github.com/microsoft/TypeScript) meant for programmatic usage only. It does not expose the binaries like `tsc` and `tsserver` because it would override the TypeScript binaries of the project. It exposes extra methods on the internal `TypeChecker` object.


## Install

```
npm install --save-dev @tsd/typescript
```


## Usage

This package is just TypeScript with some private methods exposed that [tsd](https://github.com/SamVerschueren/tsd) needs for enhanced type checking.

- `isTypeIdenticalTo(a: Type, b: Type)`: Check if two types are identical to each other. [More info...](https://github.com/microsoft/TypeScript/blob/v4.2.4/doc/spec-ARCHIVED.md#3.11.2)
- `isTypeSubtypeOf(a: Type, b: Type)`: Check if type `a` is a subtype of type `b`. [More info...](https://github.com/microsoft/TypeScript/blob/v4.2.4/doc/spec-ARCHIVED.md#3.11.3)
- `isTypeAssignableTo(a: Type, b: Type)`: Check if type `a` is assignable to type `b`.
- `isTypeDerivedFrom(a: Type, b: Type)`: Check if type `a` is derived from type `b`. [More info...](https://github.com/SamVerschueren/tsd-typescript/blob/master/scripts/utils/replacements.js#L65-L74)
- `isTypeComparableTo(a: Type, b: Type)`: Check if type `a` is comparable to type `b`. [More info...](https://github.com/SamVerschueren/tsd-typescript/blob/master/scripts/utils/replacements.js#L77-L86)
- `areTypesComparable(a: Type, b: Type)`: Check if type `a` is comparable to type `b` and `b` is comparable to type `a`. [More info...](https://github.com/SamVerschueren/tsd-typescript/blob/master/scripts/utils/replacements.js#L89-L98)


## Related

- [tsd](https://github.com/tsdjs/tsd) - Check TypeScript type definitions

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_Source: https://npm.io/package/@tsd/typescript · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._