# basarat/typescript-book

:books: The definitive guide to TypeScript and possibly the best TypeScript book :book:. Free and Open Source 🌹

Repository: https://github.com/basarat/typescript-book
Canonical: https://ross.abutalabs.com/products/typescript-book
Homepage: https://basarat.gitbook.io/typescript/
Language: TypeScript
License: NOASSERTION
License Family: other
Topics: typescript, typescript-book, typescript-community, free, open-source
Last push: 2024-06-29T11:46:59+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4183, "days_push": 795, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 21552, forks 2592 (observed 2026-08-28T04:11:31.818977+00:00)

## What it is
TypeScript Deep Dive is a free, open-source online book by Basarat Ali Syed that teaches professional TypeScript, from JavaScript fundamentals to the type system, compiler internals, and tooling. It is published via GitBook and built from community lessons on Stack Overflow and DefinitelyTyped.

## Use cases
- learn typescript from scratch
- understand typescript type system in depth
- free typescript book for beginners
- prepare for a typescript job interview
- migrate a javascript project to typescript
- learn typescript compiler internals
- best practices and style guide for typescript

## When to choose
- you want a free, well-reviewed, comprehensive TypeScript learning resource
- you prefer reading a structured book with code examples over scattered blog posts
- you need coverage from basics to advanced topics like compiler internals

## When to avoid
- you need up-to-the-minute coverage of the newest TypeScript releases, as the book is in maintenance mode
- you want interactive exercises or video courses rather than prose
- you need official normative documentation rather than a community-authored guide

## Facets
- artifact type: learning-resource
- maturity: maintenance
- function: documentation, developer-tools
- domain: tutorials, programming-languages, web-development, developer-tools
- platform: browser, cross-platform
- tags: typescript, book, gitbook, free, open-source, education, web-server, nodejs

## Member repositories
- basarat/typescript-book (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:31.818977+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 2026-08-29T16:57:56.611028+00:00, confidence not recorded.
  - readme: https://github.com/basarat/typescript-book (fetched 2026-08-28T04:11:31.818977+00:00, sha c448ee2775e1)
  - homepage: https://basarat.gitbook.io/typescript/ (fetched 2026-08-29T07:56:53.431929+00:00, sha 0f6d932ce2c9)
- Data as of 2026-08-30T08:39:29.467469+00:00.