Splunk Frontend Engineer Interview: Rounds, Questions and Preparation

What the job involves

Frontend Engineers at global tech product companies build and maintain user interfaces for web applications used by customers worldwide. They work with designers, backend engineers, and product managers to ship features, optimize performance, and ensure accessibility across browsers and devices. Day to day involves writing JavaScript/TypeScript, reviewing code, debugging UI issues, and collaborating in agile teams.

Role and Technical Knowledge

1. 1

   Explain the difference between let, const, and var in JavaScript.

   Cover scoping (block vs function), hoisting, temporal dead zone, and reassignment rules. Mention why const is preferred for immutable bindings.

2. 2

   How does the virtual DOM work in React, and why is it useful?

   Describe how React creates a lightweight tree, diffs it on state changes, and batches updates to minimize real DOM operations. Mention reconciliation and keys.

3. 3

   What are the key considerations for making a web page responsive?

   Discuss viewport meta tag, relative units (%, rem, vw), media queries, Flexbox/Grid, and mobile-first approach. Mention testing on multiple screen sizes.

4. 4

   Explain event delegation and when you would use it.

   Describe attaching a single listener to a parent to handle events from children via bubbling. Use cases: dynamic lists, performance optimization, fewer listeners.

Practical Scenarios

1. 5

   You need to build a searchable, sortable table of 10,000 rows. How would you approach performance?

   Mention virtualization/windowing (react-window), debouncing search input, memoization, server-side pagination, and avoiding unnecessary re-renders.

2. 6

   A page is loading slowly. How would you diagnose and fix it?

   Use Lighthouse, Chrome DevTools (Network, Performance), check bundle size, code splitting, lazy loading, image optimization, and caching headers.

3. 7

   How would you handle a bug where a component re-renders infinitely?

   Identify setState in render or useEffect without proper dependency array. Explain dependency arrays, useCallback/useMemo, and React strict mode warnings.

4. 8

   You need to fetch data from an API and display it with loading and error states. Walk through your implementation.

   Cover useEffect with async function, state for loading/error/data, cleanup with AbortController, and graceful UI fallbacks.

Behavioural and HR

1. 9

   Tell me about a time you had to learn a new technology quickly for a project.

   Use STAR method. Highlight the learning approach (docs, tutorials, small prototype), time constraint, and positive outcome.

2. 10

   Describe a situation where you disagreed with a teammate on a technical approach.

   Show respect, data-driven discussion, willingness to compromise, and focus on project goals. Avoid blaming others.

3. 11

   Why do you want to work as a frontend engineer at a global tech company?

   Connect personal interest in user experience, scale of impact, and eagerness to learn from diverse teams. Mention specific technologies or product areas.

4. 12

   How do you handle tight deadlines and multiple priorities?

   Discuss prioritization (impact vs effort), communication with stakeholders, breaking tasks down, and using tools like Trello/Jira. Give a concrete example.

Coding and Problem Solving

1. 13

   Write a function to debounce another function.

   Implement with setTimeout and clearTimeout. Explain use cases like search input or window resize. Mention leading/trailing options.

2. 14

   Given an array of objects, write code to group them by a property.

   Use reduce to build an object keyed by the property. Discuss handling missing keys and performance for large arrays.

3. 15

   Implement a simple counter component in React with increment and decrement buttons.

   Use useState, event handlers, and display current count. Mention accessibility (aria-live) and avoiding direct state mutation.

4. 16

   How would you flatten a nested array without using Array.flat?

   Use recursion or reduce with concat. Discuss stack overflow for deep nesting and iterative alternatives.