Master frontend interview questions with AI-generated practice. Prepare for JavaScript, React, CSS, TypeScript, performance optimization, and system design rounds at top tech companies.
Frontend interview questions assess your ability to build user interfaces, write clean JavaScript/TypeScript, work with modern frameworks, and optimize web performance. These interviews test your understanding of browser APIs, CSS layouts, state management, and frontend architecture. Whether you're preparing for junior or senior frontend engineer roles at FAANG companies, comprehensive practice is essential.
Typical frontend interview rounds:
Core JavaScript knowledge is tested in every frontend interview.
Modern frontend roles require deep knowledge of React or similar frameworks.
CSS skills are essential for building beautiful, responsive interfaces.
Senior roles require deep understanding of web performance.
Frontend interviews often ask you to build components from scratch. Practice these:
Debounced search, keyboard navigation, async data fetching.
CRUD operations, filtering, local storage persistence.
Navigation, autoplay, touch/swipe support, lazy loading.
Sorting, filtering, pagination, column resizing.
Focus trap, escape key handling, accessibility (ARIA).
Intersection Observer, virtualization, loading states.
A closure is a function that remembers its outer variables and can access them.
function createCounter() {
let count = 0;
return function() {
return ++count;
};
}
const counter = createCounter();
counter(); // 1
counter(); // 2JavaScript is single-threaded. The event loop handles async operations via the callback queue.
console.log('1');
setTimeout(() => console.log('2'), 0);
Promise.resolve().then(() => console.log('3'));
console.log('4');
// Output: 1, 4, 3, 2Debounce: Wait until user stops. Throttle: Execute at regular intervals.
// Debounce - search input
function debounce(fn, delay) {
let timeoutId;
return function(...args) {
clearTimeout(timeoutId);
timeoutId = setTimeout(() => fn(...args), delay);
};
}Heavy on algorithms + JavaScript. Expect to code on a whiteboard/doc. Accessibility questions.
Build UI components from scratch. Strong React focus. Expect system design for senior roles.
Leadership principles + coding. Component building + performance optimization.
Focus on design and UX. CSS mastery required. Attention to pixel-perfect details.
Music player UI challenges. State management and real-time updates focus.
Design-focused. Build beautiful UI components. Strong CSS and animation skills needed.
Master closures, promises, async/await, event loop, prototypes. Practice implementing common utilities (debounce, throttle, deep clone, flatten array).
Master hooks (useState, useEffect, useRef, useMemo, useCallback). Understand reconciliation, virtual DOM, and state management patterns.
Practice CSS layouts (Flexbox, Grid), responsive design. Build 5-10 components from scratch (autocomplete, modal, carousel, dropdown).
Practice frontend system design (design Twitter feed, design Google Docs). Do timed mock interviews. Review performance optimization and accessibility.
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