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JavaScript Questions

A long list of advanced JavaScript quiz questions with explanations hidden under each one.

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Licence
MIT
Language
—
Last update
2.3 years ago
Type
Learning resource

No commits in over a year — check for forks or alternatives before adopting.

What it is

This is a collection of JavaScript quiz questions, each showing a short code snippet and asking what it outputs. Answers and explanations are in collapsed sections below each question, so you can guess first and then check. The README says it covers basic to advanced topics such as hoisting, scope, `this`, type coercion and object references. The repo was created in 2019 and the README notes that newer JavaScript features are not covered.

  • Work through a question, predict the output, then expand the answer to compare
  • Use the questions as practice for interview preparation
  • Read the explanations to understand hoisting, the temporal dead zone, and reference vs. value behavior
  • Share the questions with a study group, with the author's requested reference to the repo

Great for

  • Developers preparing for JavaScript coding interviews
  • People who want to test their understanding of JavaScript behavior
  • Learners who already know the basics and want to study tricky edge cases
  • Anyone refreshing knowledge of JavaScript after a break

Not ideal for

  • Complete beginners, since the questions assume some prior JavaScript knowledge
  • People who want current language features, because the README says the questions reflect syntax and behavior from 2019
  • People looking for a structured course, since this is a list of standalone quiz questions
Step-by-step guide: how to use JavaScript QuestionsInstall, first run, examples, tips and FAQs
Front End Interview Handbook vs JavaScript QuestionsJavaScript Questions vs Modern JavaScript Cheatsheet

How to get it

  1. 1

    Read it online

    Clone the repository

    git clone https://github.com/lydiahallie/javascript-questions
  2. 2

    Run it

    • Open the README on GitHub or in the cloned folder
    • Read a question and predict the output before opening the answer
    • Expand the collapsed answer section to compare your prediction with the explanation
    • Choose a translation from the list in the README if you prefer another language
  3. 3

    Get the most out of it

    • Predict each answer on paper before expanding the explanation
    • Run the snippets in a browser console or Node.js to see the real output
    • Revisit questions you got wrong and explain the reason in your own words
    • Check the translations list if you want the questions in another language

Downloads

Source code (.zip)master branch · straight from GitHub

Strengths

  • Explanations accompany each question, so the reasoning is visible as well as the answer
  • Covers many subtle behaviors that often trip people up
  • Translated into about 20 languages according to the README

Trade-offs

  • Content is based on JavaScript as of 2019 and does not cover newer language features
  • The README is truncated here, so the full list of questions could not be verified
  • Not a software project, so there is nothing to install or run

Stats synced from GitHub. The assessment above was drafted with AI from the project's README on 2026-10-29 and may miss recent changes — check the README before relying on a command. MIT licence: free to use, modify and distribute, including commercially, as long as you keep the copyright notice.