# addyosmani/essential-js-design-patterns

Repo for my 'Learning JavaScript Design Patterns' book

Repository: https://github.com/addyosmani/essential-js-design-patterns
Canonical: https://ross.abutalabs.com/products/essential-js-design-patterns
Homepage: http://addyosmani.com/resources/essentialjsdesignpatterns/book/
Language: HTML
License Family: other
Last push: 2021-08-01T13:59:43+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 5639, "days_push": 1858, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4905, forks 804 (observed 2026-08-28T04:09:02.196530+00:00)

## What it is
The open-source repository for Addy Osmani's book 'Learning JavaScript Design Patterns', authored in HTML and readable free online. It teaches reusable design pattern solutions for common problems in JavaScript development.

## Use cases
- learn javascript design patterns
- understand module and observer patterns in js
- free online book on software design patterns
- reference for common javascript coding patterns
- improve javascript architecture skills

## When to choose
- you want a free, well-regarded introduction to design patterns in JavaScript
- you are a new or intermediate JS developer exploring patterns
- you want to read or contribute to the book's source

## When to avoid
- you need patterns for languages other than JavaScript
- you need a commercial license or derivative works (CC BY-NC-ND restricts reuse)
- you need up-to-date ES2024+ content, as the book is older

## Facets
- artifact type: learning-resource
- maturity: maintenance
- function: documentation, developer-tools
- domain: web-development, programming-languages, tutorials, education
- platform: -
- tags: design-patterns, javascript, book, free-online-book, oreilly, web-server, nodejs

## Member repositories
- addyosmani/essential-js-design-patterns (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:02.196530+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 2026-08-29T18:18:07.390505+00:00, confidence not recorded.
  - readme: https://github.com/addyosmani/essential-js-design-patterns (fetched 2026-08-28T04:09:02.196530+00:00, sha 58470ece88c1)
  - homepage: http://addyosmani.com/resources/essentialjsdesignpatterns/book/ (fetched 2026-08-29T09:00:11.987948+00:00, sha 1f7322f25456)
- Data as of 2026-08-30T08:39:29.467469+00:00.