We selected the root. This means that we're currently viewing the
Transition that rendered the whole screen. In laymans terms this is
really "Initial Paint". Once we add subtree selection, then the
equivalent should be called "Transition" since in that case it's really
about a Transition within the page. So if you've selected an Activity
tree this should be called "Transition".
Once we add the environment support to the timeline. The first entry on
the timeline should also be called "Initial Paint" when you haven't
selected an Activity and "Transition" when you have.
Technically they're both meant to be "Transition" but nobody thinks of
initial load as a "Transition" from the previous MPA page.
<img width="1214" height="419" alt="Screenshot 2025-09-29 at 5 18 58 PM"
src="https://github.com/user-attachments/assets/cae263e3-133c-4fa9-9587-a7b2344199f4"
/>
This brings the Suspense boundary that's switching into view so that
when you play the loading sequence you can see how it plays out.
Otherwise it's really hard to find where things are changing.
This assumes we'll also scroll synchronize the suspense tab which will
bring it into view there too.
When you double click it will hide or show by jumping to the selected
index or one step before the selected.
Let's you go from a suspense boundary into the timeline to find its
position. I also highlight the step in the timeline when you hover the
rect.
This only works if it's in the selected root but all of those should be
merged into one single timeline.
One thing that's weird about the SuspenseNodes now is that they
sometimes gets deleted but not always when they're resupended. Nested
ones maybe? This means that if you double click to hide it, you can't
double click again to show it. This seems like an unrelated bug that we
should fix.
We could potentially repurpose the existing "Suspend" button in the
toolbar to do this too, or maybe add another icon there.
Stacked on #34625.
This is a nice way to step through the timeline and simulate the visuals
on screen as you do it. It's also convenient to step through one at a
time, especially with the forwards button.
However, the secondary purpose of this is that it helps anchor the UI
visually as something like a timeline like in a video so that the
timeline itself becomes more identifiable.
https://github.com/user-attachments/assets/cb367c8e-9efb-4a00-a58e-4579be20beb8
The settings dialog appears on all tabs and should be reachable from
Suspense tab too. It's a bit weird because it's not contextual to the
tab and it shows you whatever your last settings tab was opened. Maybe
it should default to opening to the current tab's settings?
There aren't any Suspense specific settings yet but there definitely
will be. We could move the "Show all" into settings but it might be
frequently that you want to check why something isn't suspending a
Suspense boundary or test SSR streaming.
However, the general settings still apply to the Suspense tab. E.g.
switching dark/light mode.
<img width="857" height="233" alt="Screenshot 2025-09-27 at 12 35 05 PM"
src="https://github.com/user-attachments/assets/4a38e94f-2074-4dce-906b-9a1c40bccb9b"
/>
It's possible for the children to overflow the bounding rect of the root
in general when they overflow in the DOM. However even when it doesn't
overflow in the DOM, the bounding rect of the root can shrink while the
content is suspended. In fact, it's very likely.
Originally I thought we didn't need to consider this recursively because
document scrolling takes absolute positioned content into account but
because we're using nested overflow scrolling, we have to manually
compute this.
One thing that always bothered me is that the collapse buttons on either
side of the toolbar looks like left/right buttons which would conflict
with some steps buttons I plan to add. Another issue is that we'll need
to add more tool buttons to the top and probably eventually a Search
field. Ideally this whole section should line up vertically with the
height of the title row.
I also realized that all UIs that have some kind of timeline control
(and play/pause/skip) do that in the bottom below the content. E.g.
music players and video players all do that. We're better off playing
into that structure since that's the UI analogy we're going for here.
Makes it clearer what the weird timeline is for.
By moving it to the bottom it also frees up the top for the collapse
buttons and more controls.
__Horizontal__
<img width="794" height="809" alt="Screenshot 2025-09-26 at 3 40 35 PM"
src="https://github.com/user-attachments/assets/dacad9c4-d52f-4b66-9585-5cc74f230e6f"
/>
__Vertical__
<img width="570" height="812" alt="Screenshot 2025-09-26 at 3 40 53 PM"
src="https://github.com/user-attachments/assets/db225413-849e-46f1-b764-8fbd08b395c4"
/>
Tracks the environment names of the I/O in each SuspenseNode and sent it
to the front end when the suspenders change.
In the front end, every child boundary should really be treated as it
has all environment names of the parents too since they're blocked by
the parent too. We could do this tracking on backend but if there's ever
one added on the root would need to be send for every child.
This lets us highlight which subtrees are blocked by content on the
server.
---------
Co-authored-by: Sebastian "Sebbie" Silbermann <silbermann.sebastian@gmail.com>
When there are no named Activities we should hide the tree side panel
(and the button to show it). Since it's not implemented yet there are
never any ones so it's always hidden.
When the search query changes, we kick off a transition that updates the
search query in a reducer for TreeContext. The search input is also
using this value for an `input` HTML element.
For a larger applications, sometimes there is a noticeable delay in
displaying the updated search query. This changes the approach to also
keep a local synchronous state that is being updated on a change
callback.
A Flow upgrade removed the bundled library definitinos for
SynthaticEvent and we probably want to use our internal definitions.
Those are not properly typed at this point yet, but we can look into
that as a followup.
This update was a bit more involved.
- `React$Component` was removed, I replaced it with Flow component
types.
- Flow removed shipping the standard library. This adds the environment
libraries back from `flow-typed` which seemed to have changed slightly
(probably got more precise and less `any`s). Suppresses some new type
errors.
This is intended to be used by various client side resources where the
transfer size is interesting to know how it'll perform in various
network conditions. Not intended to be added by the server.
For now it's only added internally by DevTools itself on img/css but
I'll add it from Flight Client too in a follow up.
This now shows this as the "transfer size" which is the encoded body
size + headers/overhead. Where as the "fileSize" that I add to images is
the decoded body size, like what you'd see on disk. This is what Chrome
shows so it's less confusing if you compare Network tab and this view.
We currently only track the reason something might suspend in
development mode through debug info but this excludes some cases. As a
result we can end up with boundary that suspends but has no cause. This
tries to detect that and show a notice for why that might be. I'm also
trying to make it work with old React versions to cover everything.
In production we don't track any of this meta data like `_debugInfo`,
`_debugThenable` etc. so after resolution there's no information to take
from. Except suspensey images / css which we can track in prod too. We
could track lazy component types already. We'd have to add something
that tracks after the fact if something used a lazy child, child as a
promise, hooks, etc. which doesn't exist today. So that's not backwards
compatible and might add some perf/memory cost. However, another
strategy is also to try to replay the components after the fact which
could be backwards compatible. That's tricky for child position since
there's so many rules for how to do that which would have to be
replicated.
If you're in development you get a different error. Given that we've
added instrumentation very recently. If you're on an older development
version of React, then you get a different error. Unfortunately I think
my feature test is not quite perfect because it's tricky to test for the
instrumentation I just added.
https://github.com/facebook/react/pull/34146 So I think for some
prereleases that has `_debugOwner` but doesn't have that you'll get a
misleading error.
Finally, if you're in a modern development environment, the only reason
we should have any gaps is because of throw-a-Promise. This will
highlight it as missing. We can detect that something threw if a
Suspense boundary commits with a RetryCache but since it's a WeakSet we
can't look into it to see anything about what it might have been. I
don't plan on doing anything to improve this since it would only apply
to new versions of React anyway and it's just inherently flawed. So just
deprecate it #34032.
Note that nothing in here can detect that we suspended Transition. So
throwing at the root or in an update won't show that anywhere.
