Frontend · Mid-level · Theory

Users complain that the page stutters and lags when they scroll. How would you look for the cause, and what role might reflow and repaint play here?

~4 min by voice

How to approach it

They're checking whether the candidate understands the browser's rendering pipeline (style -> layout -> paint -> composite) and can methodically find the bottleneck with DevTools instead of guessing. It's also important to know the typical causes of scroll jank and concrete ways to fix them.

Have you seen this question in a real interview?

Answers0

Avg. score—

Strong—

Practiced0

Topics

rendering performance

Similar questions

A service running on G1 periodically has pauses of one to two seconds, and it's hurting latency. What would you do, and when is it worth looking at a different garbage collector? Mid-level How is reflow different from repaint, and why does frequent reflow hurt performance? Junior A load test showed that at 500 requests per second, response time grew from 200 milliseconds to three seconds. How would you track down the cause, and what would you put in the report? Mid-level How do you track down a performance bottleneck in Python code? What's the most telling case from your own experience? Senior What makes a React component re-render, and how do you avoid unnecessary re-renders? Junior

Answer by voice

The interviewer will ask this question and listen. Think out loud and ask for a hint if you need one. When you're done, pause or tap “That's my answer”. In about a minute, your score and the points you covered show up here.

Best with headphones · ~4 min