JavaScript Interview Questions Asked by Specific Companies

JavaScript Interview Questions Asked by Specific Companies

Here are real JS interview questions asked by specific companies.

Amazon

• sum(1)(2)(3)(4)..(n): implement a curried sum function.
• Debounce: implement debounce from scratch.
• Promise.polyfill: implement Promise.all.
• Event loop: predict the output of mixed sync, microtask, and macrotask code.

Flipkart

• Debouncing: implement debounce and explain when to use it.
• Event delegation: explain and implement.
• Deep clone: implement a deep clone function.
• Array methods: implement map, filter, reduce polyfills.

Walmart

• Throttling: implement throttle from scratch.
• Debouncing vs Throttling: explain the difference and when to use each.
• Prototypes: explain prototypal inheritance.
• Closures: explain closures with a real example.

Ola

• async and defer: explain the difference and their impact on rendering.
• Event loop: explain how JS handles async.
• this keyword: explain the binding rules.

Oyo

• Event bubbling: explain event propagation.
• Event delegation: implement with a real example.
• stopPropagation: explain and when to use.

Google, Microsoft, Uber

• Machine coding: build a UI component in 90 minutes.
• System design: design a large frontend system.
• DSA: data structures and algorithms.
• Deep JS: closures, event loop, this, promises, prototypes.

The Takeaway

Company-specific questions: Amazon (currying, debounce, Promise.all), Flipkart (debounce, event delegation, deep clone), Walmart (throttle, debounce vs throttle, prototypes), Ola (async/defer, event loop), Oyo (event bubbling, delegation). Top companies also ask machine coding, system design, and DSA.