# leonardomso/33-js-concepts

📜 33 JavaScript concepts every developer should know.

Repository: https://github.com/leonardomso/33-js-concepts
Canonical: https://ross.abutalabs.com/products/33-js-concepts
Homepage: https://33jsconcepts.com/
Language: JavaScript
License: MIT
License Family: permissive
Topics: javascript, concepts, nodejs, react, angular, programming, javascript-programming, javascript-closures, javascript-engines, primitive-types, es6, es6-javascript, hacktoberfest
Last push: 2026-08-02T14:51:44+00:00

## Health v2 (maintenance only)
Score: 75/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 95, release rhythm 35, longevity 100
- inputs: {"age_days": 2920, "days_push": 31, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 66516, forks 9137 (observed 2026-08-28T04:12:20.727750+00:00)

## What it is
A curated learning guide covering 33 core JavaScript concepts (plus 29 advanced ones) with explanations, code examples, diagrams, and links to articles, videos, and books. It originated as a popular GitHub repository and now also lives as a full documentation website.

## Use cases
- learn javascript fundamentals from scratch
- prepare for javascript technical interviews
- understand closures and the event loop
- fill knowledge gaps as a self-taught developer
- find curated resources for javascript concepts
- learn modern es6+ javascript syntax
- study javascript concepts in a structured learning path

## When to choose
- you want a structured, free path to deeply understand JavaScript rather than just syntax
- you are preparing for technical interviews and need core concepts cold
- you are a beginner or self-taught developer wanting curated articles, videos, and examples per topic

## When to avoid
- you need a runnable library, framework, or tool rather than learning material
- you want framework-specific tutorials like React or Angular internals
- you prefer interactive courses with graded exercises over reading and self-practice

## Facets
- artifact type: learning-resource
- maturity: active
- function: documentation, developer-tools
- domain: programming-languages, tutorials, web-development, education
- platform: browser, cross-platform
- tags: javascript, learning-guide, es6, interview-prep, curated-resources, awesome-list

## Member repositories
- leonardomso/33-js-concepts (main) score 75

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:12:20.727750+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 2026-08-29T16:16:27.955343+00:00, confidence not recorded.
  - readme: https://github.com/leonardomso/33-js-concepts (fetched 2026-08-28T04:12:20.727750+00:00, sha 87dd16e2b0f5)
  - homepage: https://33jsconcepts.com/ (fetched 2026-08-28T17:53:14.313316+00:00, sha 367af963fe19)
  - site_page: https://33jsconcepts.com/getting-started/about (fetched 2026-08-28T17:53:14.321805+00:00, sha ee303bbe478a)
  - site_page: https://33jsconcepts.com/getting-started/how-to-learn (fetched 2026-08-28T17:53:14.323582+00:00, sha 7be084dfec2c)
  - site_page: https://33jsconcepts.com/getting-started/prerequisites (fetched 2026-08-28T17:53:14.325342+00:00, sha b3dfadc14267)
  - site_page: https://33jsconcepts.com/getting-started/learning-paths (fetched 2026-08-28T17:53:14.327087+00:00, sha de2a1f96ffce)
  - site_page: https://33jsconcepts.com/beyond/getting-started/overview (fetched 2026-08-28T17:53:14.331198+00:00, sha 16c50aaf8a9a)
  - site_page: https://33jsconcepts.com/concepts/modern-js-syntax (fetched 2026-08-28T17:53:14.328876+00:00, sha acc0acf23700)
- Data as of 2026-08-30T08:39:29.467469+00:00.