Michal Mocny
Michal Mocny
A small group of engineers spent about 30 minutes reviewing existing Performance API and Performance Timeline documentation to search for any opportunities for improvement. We found many examples of improvement...
I was recently surprised to find a mismatch between LCP reported by DevTools timeline and Web Vitals extension. It looks like the cause is simply because the [Web Platform api...
For every interaction you have: - A single interactionId - A few Event Timings which share that interactionId, potentially with different presentation times - A single "longest" Event, whose duration...
Fun project! :D I figured I would leave some comments after reading the README.md, going through some examples, and reading a bit of the source for the first time: *...
Screenshot:  (notice that processing time ends after the paint/commit on main thread). Note: I was using the experimental PR of Web Vitals Extension to...
[Margin collapsing](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Box_Model/Mastering_margin_collapsing) can sometimes turn a small shift on a child element into a large shift on a parent/sibling element. For example: * Visit this demo https://cls-iframe-problem.glitch.me/iframe.html * Using console,...
Context: a webpage which uses cross-frame communication (e.g. postMessage) to make changes to an another iframe in direct response to interactions. Visually, this looks exactly as if the shift happened...
The Usage Example does showcase ignoring recent input and does include a comment: ` // Only count layout shifts without recent user input.`, but I do not see this explicitly...
Today, [Input Exclusion](https://wicg.github.io/layout-instability/#sec-input-exclusion) states that `Excluding inputs generally include mousedown, keydown, pointerdown, and change events` This "generally" opens up some flexibility, however, we may want to put in a note...
Ideally, layout shifts would not be reported for content which shifted while within viewport but still completely obscured and not visible to users. (For example, when covered by a full...