Top 10 JavaScripte Questions in 2026
Top 10 JavaScripte Questions in 2026 uses verified RivoHire qbank answers. Start with the strongest short answer, then review tradeoffs, scenarios, mistakes, and interview wording.
Quick definition
Top 10 JavaScripte Questions in 2026 uses verified RivoHire qbank answers. Start with the strongest short answer, then review tradeoffs, scenarios, mistakes, and interview wording.
Quick Summary
| Topic | Questions | Source | Company Claims |
|---|---|---|---|
| Javascript | 10 | MongoDB qbank | Only shown when present in qbank |
Scenario Questions
- A dashboard freezes while processing a large response on the browser main thread. I would split CPU-heavy work, keep promise chains predictable, and verify improvement with interaction latency and long-task measurements.
- A JavaScript change causes slower responses after traffic increases. I would isolate the hot path, apply the smallest reversible fix, and verify the result with latency, error rate, and rollback readiness.
- A JavaScript change causes slower responses after traffic increases. I would isolate the hot path, apply the smallest reversible fix, and verify the result with latency, error rate, and rollback readiness.
- A JavaScript change causes slower responses after traffic increases. I would isolate the hot path, apply the smallest reversible fix, and verify the result with latency, error rate, and rollback readiness.
Common Mistakes
- Wrong approach: event-loop is good because it is faster. Why it fails: Speed without workload, correctness, and operational context is not an engineering answer. Better answer: I would compare the workload, failure mode, and maintenance cost before using event-loop, then verify the result with production metrics.
- Wrong approach: closures is good because it is faster. Why it fails: Speed without workload, correctness, and operational context is not an engineering answer. Better answer: I would compare the workload, failure mode, and maintenance cost before using closures, then verify the result with production metrics.
- Wrong approach: scope is good because it is faster. Why it fails: Speed without workload, correctness, and operational context is not an engineering answer. Better answer: I would compare the workload, failure mode, and maintenance cost before using scope, then verify the result with production metrics.
- Wrong approach: promises is good because it is faster. Why it fails: Speed without workload, correctness, and operational context is not an engineering answer. Better answer: I would compare the workload, failure mode, and maintenance cost before using promises, then verify the result with production metrics.
- Wrong approach: setTimeout with zero delay runs immediately. Why it fails: It waits for the current stack and microtasks to finish. Better answer: Zero delay means schedule as a macrotask as soon as the stack and microtasks are clear.
FAQ
Practice
Practice these questions in a RivoHire mock interview.
Quiz
What runs first after the synchronous call stack becomes empty?
Correct answer: microtasks run after the stack clears and before the next macrotask.
Compact Interview Questions
What is the event loop in JavaScript?
The event loop coordinates the call stack, task queues, microtasks, and asynchronous callbacks.
How do closures work in JavaScript?
A closure lets a function retain access to variables from its lexical scope after the outer function has returned.
What is the difference between var, let, and const?
var is function-scoped and hoisted, while let and const are block-scoped; const prevents reassignment.