-
-
Notifications
You must be signed in to change notification settings - Fork 1.9k
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Unnecessary unmounting/mounting children with keys #2783
Comments
Probably related to #2619 |
Was told my issues is related, so here is my case report: Whenever you remove an uncertain number of elements from a keyed list, the elements after them get remounted. The number seems to differ between environments. On my local app it's 20+, on the isolated example below it's 50+. Here is a visualization of the issue. Elements that get remounted flash red. The last 20 items should never flash, as only range 20-80 is being toggled: This doesn't happen for smaller amount of items being removed: The issue is isolated here: https://codesandbox.io/s/cocky-joliot-9gw5v |
Echoing from various discussions elsewhere: the |
good evening all :) is there undergoing work about this? thanks! |
This issue causes serious FOUC problems when rendering arrays of What is an ETA for a fix? Is it fixed in |
@jaydenseric this has been fixed in v11, introducing this fix in v10 would be a huge perf impediment I've tried in #3359 for v11 with our new diffing algo it is a net positive #3358 |
That's great news, when do you think v11 will be released? I'm currently working full time on a buildless SSR web app framework for Deno based around Preact, and this issue is a blocker. If there is no way to try a v11 prerelease, and a stable v11 if far away, I might have to reschedule my next few weeks. Also, I'm keen to contribute to improving Preact, particularly regarding Deno compatibility. Is the |
Hi all, I'm the author of tikzcd-editor and am experiencing severe performance degradation after updating Preact recently.
tikzcd-editor is rendering a grid of elements onto the viewport; we only render visible grid cells. The user can use the pan tool to pan the grid, so cells outside of the viewport need to be added while panning, and cells that go outside of the viewport get removed.
Each grid cell will be typeset using MathJax on every change, which is expensive, that's why every grid cell has a
key
set to its coordinates, so we avoid rerendering while panning. This worked fine in v10.4.1, but in v10.4.2 and the latest version v10.5.3, we experience a lot of unnecessary rerenders.Reproduction
Steps to reproduce
Here's a deployment of tikzcd-editor with v10.5.3 with a sample diagram. When trying to pan the viewport, you can see it's not smooth at all. When opening the Devtools you can see that Preact is unnecessarily unmounting/mounting elements.
Expected Behavior
Visible children should not be unmounted/remounted like in v10.4.1:
Actual Behavior
A lot of unnecessary unmounting/rendering of children as experienced in v10.4.2 and v10.5.3:
The text was updated successfully, but these errors were encountered: