Question 1

Build a debounced Search Bar

Accepted Answer

**Target Audience:** Frontend developers preparing for a machine coding round. Assumes basic React (components, `useState`), nothing about debouncing or request cancellation. **Difficulty:** Medium > **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. The output in the Verified section was produced by actually running the solution on React 19.3.1 in jsdom with a

Question 2

Build an Autocomplete / Typeahead search

Accepted Answer

**Target Audience:** Frontend developers preparing for a machine coding round. Assumes basic React state and effects; keyboard navigation, caching and ARIA roles are explained from zero. **Difficulty:** Medium > **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. The Verified output was produced by running the solution on React 19.3.1 in jsdom with a scripted dri

Question 3

Build a Signup Form with async username availability check

Accepted Answer

**Target Audience:** Frontend candidates preparing for a machine coding round. Assumes you have built a basic validated form; the [Form with validation](/interview-question/build-a-form-with-validation) question covers that ground. **Difficulty:** Medium > **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. Code excerpts are copied from the runnable solution, and

Question 4

Build a Todo App with Pagination, Filters & Optimistic Updates

Accepted Answer

**Target Audience:** Developers who can already build a local todo list (see [Build a Todo List](/interview-question/build-a-todo-list)) and now need to talk to a slow, unreliable server. Assumes useState, useEffect and keys. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary interviewers listen for. Every code excerpt is copied from the runnable solution, and the Verified section q

Question 5

Build Autocomplete / Typeahead with Debounce & Highlight

Accepted Answer

**Target Audience:** Frontend developers who can already build a basic autocomplete and want the two details that separate a demo from production: safe highlighting and race-proof requests. **Difficulty:** Medium > **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. The Verified output was produced by running the solution on React 19.3.1 in jsdom; regex and strin

FRONTEND MACHINE CODINGDECODED.

Medium

Build a debounced Search Bar

Build an Autocomplete / Typeahead search

Build a Signup Form with async username availability check

Build a Todo App with Pagination, Filters & Optimistic Updates

Build Autocomplete / Typeahead with Debounce & Highlight