# sindresorhus/type-fest

A collection of essential TypeScript types

Repository: https://github.com/sindresorhus/type-fest
Canonical: https://ross.abutalabs.com/products/type-fest
Language: TypeScript
License: CC0-1.0
License Family: permissive
Topics: typescript-definitions, typescript, types, utilities, npm-package
Last push: 2026-08-26T12:21:42+00:00

## Health v2 (maintenance only)
Score: 96/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 91, longevity 100
- inputs: {"age_days": 2730, "days_push": 7, "days_rel": 60, "gap_med": 9.0, "n_releases_24m": 39}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 17381, forks 731 (observed 2026-08-28T04:11:19.613472+00:00)

## What it is
A collection of essential TypeScript utility types that many feel should be built into the language. It is an npm package of type-only definitions that can be installed as a dependency or copy-pasted freely.

## Use cases
- make specific object properties optional in TypeScript
- exclude keys from a TypeScript type
- get the type of array elements in TypeScript
- define deeply readonly object types
- write stricter JSON-typed values in TypeScript
- find commonly needed utility types missing from TypeScript

## When to choose
- you write TypeScript and frequently need utility types like Partial, Except, or JsonObject
- you want a well-maintained, dependency-free set of type helpers
- you prefer copy-pasting types with no attribution required

## When to avoid
- your project uses TypeScript older than 5.9 or is not strict-mode
- you need runtime validation or runtime helper functions rather than types
- you work in plain JavaScript without type checking

## Facets
- artifact type: library
- maturity: active
- function: type-system, developer-tools
- domain: developer-tools, programming-languages
- platform: cross-platform
- tags: typescript, utility-types, npm-package, type-definitions, nodejs

## Member repositories
- sindresorhus/type-fest (main) score 96

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:19.613472+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:02:58.734220+00:00, confidence not recorded.
  - readme: https://github.com/sindresorhus/type-fest (fetched 2026-08-28T04:11:19.613472+00:00, sha b77ddd5d4fd8)
- Data as of 2026-08-30T08:39:29.467469+00:00.