Question 1

Build a Like Button

Accepted Answer

**Target Audience:** Beginners preparing for a frontend machine coding round. You know basic React state; promises and async code are still a little fuzzy. **Difficulty:** Easy > **How to read this doc:** Every idea is explained in plain language first, then tagged with 📌 Interview term: so you also learn the exact words an interviewer listens for. All code comes from the runnable solution next to this tutorial, and the output in section 6 was produced by actually running it on Re

Question 2

Build a Progress Bar

Accepted Answer

**Target Audience:** Beginners preparing for a frontend machine coding round. You need basic React (props, `useState`); timers in effects and the ARIA details are explained here. **Difficulty:** Easy > **How to read this doc:** Every idea is explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. Code excerpts are copied from the runnable solution; the Verified blocks are real output from React 19.3.1 in StrictM

Question 3

Build a Toggle Switch

Accepted Answer

**Target Audience:** Beginners preparing for a frontend machine coding round. You know basic React props and state; accessibility attributes are new territory. **Difficulty:** Easy > **How to read this doc:** Every idea is explained in plain language first, then tagged with 📌 Interview term: so you also learn the exact words an interviewer listens for. All code comes from the runnable solution next to this tutorial, and the output in section 6 was produced by actually running it o

Question 4

Build a Typewriter Effect

Accepted Answer

**Target Audience:** Beginners preparing for a frontend machine coding round. You know a little JavaScript and React; state machines, timeouts, effect cleanup and screen-reader techniques are explained from zero. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary interviewers expect. Every output under "Verified" was printed by running this exact solution (and one deliberately broken copy) on React 19.3.1 insi

Question 5

Build a Skeleton Loader

Accepted Answer

**Target Audience:** Beginners preparing for a frontend machine coding round. You need basic React (props, `useState`, `useEffect`); data-loading patterns and the accessibility details are explained here. **Difficulty:** Easy > **How to read this doc:** Every idea is explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. Code excerpts are copied from the runnable solution; the Verified blocks are real output fr

Question 6

Build an Accordion component

Accepted Answer

**Target Audience:** Beginners preparing for a frontend machine coding round. You need basic React (components, props, `useState`); no accessibility background is assumed. **Difficulty:** Easy > **How to read this doc:** Every idea is explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. All code excerpts are copied from the runnable solution, and every "Verified" block is real output from running it (React 19

Question 7

Build an Image Carousel

Accepted Answer

**Target Audience:** Frontend candidates preparing for a machine coding round. Assumes basic React (`useState`, props, event handlers); timers, ARIA and CSS transforms are explained from zero. **Difficulty:** Medium > **How to read this doc:** Each idea comes in plain words first, then tagged with 📌 Interview term: so you also learn the vocabulary interviewers use. The output in section 6 was produced by running the solution on React 19.3.1 in jsdom, and in headless Chromium 141 f

Question 8

Build an Image Carousel with Infinite Loop & Swipe

Accepted Answer

**Target Audience:** Frontend candidates who can already build a basic carousel and now face the "make it feel native" follow-up. Assumes React hooks; pointer events, transitions and the tricks are explained from zero. **Difficulty:** Medium > **How to read this doc:** Each idea is explained in plain words, then tagged with 📌 Interview term:. This doc assumes the fundamentals of [the basic image carousel](/interview-question/build-an-image-carousel) (wrap-around, autoplay with cle

Question 9

Build a Speed Dial Menu

Accepted Answer

**Target Audience:** Frontend candidates preparing for a machine coding round. Assumes React state and props; `inert`, staggered transitions and outside-press handling are explained here. **Difficulty:** Medium > **How to read this doc:** Plain words first, then a 📌 Interview term: callout. Logic was verified on React 19.3.1 in jsdom; layout, the real stagger, Tab order and hit testing were checked in Chromium 141, because jsdom has no layout or animation. ## 1. Why This Even Mat

Question 10

Build a Toast / Snackbar Queue with Pause on Hover

Accepted Answer

**Target Audience:** Frontend developers who can already build a basic toast system and want the harder follow-up. Assumes React hooks; the timer maths is explained from scratch. **Difficulty:** Medium > **How to read this doc:** Plain words first, then 📌 Interview term: callouts with the precise vocabulary. This doc assumes the fundamentals from [Build a Toast Notification system](/interview-question/build-a-toast-notification-system) (provider, portal, live region) and focuses o

FRONTEND MACHINE CODINGDECODED.

Easy

Build a Like Button

Build a Progress Bar

Build a Toggle Switch

Build a Typewriter Effect

Build a Skeleton Loader

Build an Accordion component

Medium

Build an Image Carousel

Build an Image Carousel with Infinite Loop & Swipe

Build a Speed Dial Menu

Build a Toast / Snackbar Queue with Pause on Hover

Build an Analog Clock

Build a Poll Widget with Live Results & Confetti

Hard

Build Connect Four

Build a Chat UI

Build the Snake Game

Build a Live Stock Ticker with throttled updates