[DevTools] Track suspensey CSS on "suspended by" #34166
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eps1lon
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Aug 11, 2025
Always show the io owner if it's not the same as the other owner.
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Same as #34166 but for Suspensey images. The trick here is to check the `SuspenseyImagesMode` since not all versions of React and not all subtrees will have Suspensey images enabled yet. The other trick is to read back from `currentSrc` to get the image url we actually resolved to in this case. Similar to how for Suspensey CSS we check if the media query would've matched. <img width="591" height="205" alt="Screenshot 2025-08-11 at 9 32 56 PM" src="https://github.com/user-attachments/assets/ac98785c-d3e0-407c-84e0-c27f86c0ecac" />
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We need to track that Suspensey CSS (Host Resources) can contribute to the loading state. We can pick up the start/end time from the Performance Observer API since we know which resource was loaded.
If DOM nodes are not filtered there's a link to the
<link>instance. The"awaited by"stack is the callsite of the JSX creating the<link>.Inspecting the link itself:
In this approach I only include it if the page currently matches the media query. It might contribute in some other scenario but we're not showing every possible state but every possible scenario that might suspend if timing changes in the current state.