How to use the JavaScript Interview Flashcards
- 1. Choose topicsPick one topic or all of them, a round size, and whether to skip cards you already know.
- 2. Flip and gradeRead the question, answer aloud, then reveal the answer and mark it known or still learning.
- 3. Review your resultsMissed cards come back later in the round. At the end see your score by topic and download the cards to revise.
What the deck covers
This deck covers the JavaScript fundamentals that trip people up in interviews: scope and hoisting, how this is decided, asynchronous code and the language's quirks. The 24 cards are grouped into 12 topics: Basics, Scope, this, Functions, Async, Objects, Arrays, DOM, Performance, ES6+, Modules, Misc. Answers are short on purpose: one or two sentences you can say out loud, which you then back up with an example from your own projects.
A card from the deck
Q: Explain the event loop.
A: JavaScript runs one call stack. Async callbacks wait in queues; when the stack is empty, all microtasks (promises) run first, then the next macrotask (timers, I/O).
Interviewers usually ask you to predict the output of a snippet mixing setTimeout and a resolved promise. Knowing that microtasks run first gets you the right order.
How to study with it
- Run the tricky cards (== vs ===, hoisting, closures in loops) in the browser console.
- Pair the event loop card with the JavaScript event loop visualizer to see the queues.
- In the JavaScript deck, cards you mark "still learning" come back three cards later in the same round, and the results screen lists them so you can download a revision sheet.
More questions from this deck
Other JavaScript questions you'll meet include:
- == vs ===?
- What is hoisting?
- call vs apply vs bind?
- Promise.all vs Promise.allSettled vs Promise.race?
- How do you remove duplicates from an array?
Frequently asked questions
Is TypeScript covered?
No. These cards cover JavaScript itself, which TypeScript builds on.
Which ECMAScript version?
Modern JavaScript (ES2015 and later), including structuredClone for deep copies.
Are the JavaScript interview flashcards free?
Yes. You can flip through every card of the JavaScript interview flashcards without signing up. When you open your results for the first time, we ask once for your name and WhatsApp number; after that the JavaScript interview flashcards and every other Uncodemy tool open straight away.