## Overview
Does a few things:
- Renames `enableSyncDefaultUpdates` to
`forceConcurrentByDefaultForTesting`
- Changes the way it's used so it's dead-code eliminated separate from
`allowConcurrentByDefault`
- Deletes a bunch of the gated code
The gates that are deleted are unnecessary now. We were keeping them
when we originally thought we would come back to being concurrent by
default. But we've shifted and now sync-by default is the desired
behavior long term, so there's no need to keep all these forked tests
around.
I'll follow up to delete more of the forked behavior if possible.
Ideally we wouldn't need this flag even if we're still using
`allowConcurrentByDefault`.
stacked on #26753
Adds support for preloading bootstrapModules. We don't yet support
modules in Float's public interface but this implementation should be
compatible with what we do when we add it.
This PR adds a preload for bootstrapScripts. preloads are captured
synchronously when you create a new Request and as such the normal logic
to check if a preload already exists is skipped.
clearContainer and clearSingleton both assumed scripts could be safely
removed from the DOM because normally once a script has been inserted
into the DOM it is executable and removing it, even synchronously, will
not prevent it from running. However There is an edge case in a couple
browsers (Chrome at least) where during HTML streaming if a script is
opened and not yet closed the script will be inserted into the document
but not yet executed. If the script is removed from the document before
the end tag is parsed then the script will not run. This change causes
clearContainer and clearSingleton to retain script elements. This is
generally thought to be safe because if we are calling these methods we
are no longer hydrating the container or the singleton and the scripts
execution will happen regardless.
This solves an issue where if you inject a hidden field in the beginning
of the form, we might mistakenly hydrate the injected one that was part
of an action.
I'm not too happy about how specific this becomes. It's similar to Float
but in general we don't do this deep comparison.
See https://github.com/vercel/next.js/issues/50087
Currently when React generates rel=preload link tags for script/stylesheet resources, it will not carryover nonce and fetchpriority values if specified on the original elements.
This change ensures that the preload links use the nonce and fetchPriority values if they were specified.
…affiliates.
## Summary
There were 8 different places where the copyright comment was wrong.
Rewrote from "Copyright (c) Facebook, Inc. and its affiliates." to
"Copyright (c) Meta Platforms, Inc. and its affiliates."
## How did you test this change?
No code was changed. Comment was still a comment after changes.
Co-authored-by: Dennis Moradkhani <denmo530@student.liu.se>
Previously, we'd call and use getSnapshot on the second render resulting
in `Warning: Text content did not match. Server: "Nay!" Client: "Yay!"`
and then `Error: Text content does not match server-rendered HTML.`.
Fixes#26095. Closes#26113. Closes#25650.
---------
Co-authored-by: eps1lon <silbermann.sebastian@gmail.com>
Stacked on top of #26735.
This allows a framework to add a `$$FORM_ACTION` property to a function.
This lets the framework return a set of props to use in place of the
function but only during SSR. Effectively, this lets you implement
progressive enhancement of form actions using some other way instead of
relying on the replay feature.
This will be used by RSC on Server References automatically by
convention in a follow up, but this mechanism can also be used by other
frameworks/libraries.
This allows us to emit extra ephemeral data that will only be used on
server rendered forms.
First I refactored the shouldSkip functions to now just do that work
inside the canHydrate methods. This makes the Config bindings a little
less surface area but it also helps us optimize a bit since we now can
look at the code together and find shared paths.
canHydrate returns the instance if it matches, that used to just be
there to refine the type but it can also be used to just return a
different instance later that we find. If we don't find one, we'll bail
out and error regardless so no need to skip past anything.
in https://github.com/facebook/react/pull/26738 we added nonce to the
ResponseState. Initially it was used in a variety of places but the
version that got merged only included it with the external fizz runtime.
This PR updates the config for the external fizz runtime so that the
nonce is encoded into the script chunks at request creation time.
The rationale is that for live-requests, streaming is more likely than
not so doing the encoding work at the start is better than during flush.
For cases such as SSG where the runtime is not required the extra
encoding is tolerable (not a live request). Bots are an interesting case
because if you want fastest TTFB you will end up requiring the runtime
but if you are withholding until the stream is done you have already
sacrificed fastest TTFB and the marginal slowdown of the extraneous
encoding is hopefully neglibible
I'm writing this so later if we learn that this tradeoff isn't worth it
we at least understand why I made the change in the first place.
This adds an experimental hook tentatively called useOptimisticState.
(The actual name needs some bikeshedding.)
The headline feature is that you can use it to implement optimistic
updates. If you set some optimistic state during a transition/action,
the state will be automatically reverted once the transition completes.
Another feature is that the optimistic updates will be continually
rebased on top of the latest state.
It's easiest to explain with examples; we'll publish documentation as
the API gets closer to stabilizing. See tests for now.
Technically the use cases for this hook are broader than just optimistic
updates; you could use it implement any sort of "pending" state, such as
the ones exposed by useTransition and useFormStatus. But we expect
people will most often reach for this hook to implement the optimistic
update pattern; simpler cases are covered by those other hooks.
Currently there is no way to provide a nonce when using
`ReactDOM.preinit(..., { as: 'script' })`
This PR adds `nonce?: string` as an option
While implementing this PR I added a test to also show you can pass
`integrity`. This test isn't directly related to the nonce change.
This hook reads the status of its ancestor form component, if it exists.
```js
const {pending, data, action, method} = useFormStatus();
```
It can be used to implement a loading indicator, for example. You can
think of it as a shortcut for implementing a loading state with the
useTransition hook.
For now, it's only available in the experimental channel. We'll share
docs once its closer to being stable. There are additional APIs that
will ship alongside it.
Internally it's implemented using startTransition + a context object.
That's a good way to think about its behavior, but the actual
implementation details may change in the future.
Because form elements cannot be nested, the implementation in the
reconciler does not bother to keep track of multiple nested "transition
providers". So although it's implemented using generic Fiber config
methods, it does currently make some assumptions based on React DOM's
requirements.
I found a couple scenarios where preloads were issued too aggressively
1. During SSR, if you render a new stylesheet after the preamble flushed
it will flush a preload even if the resource was already preloaded
2. During Client render, if you call `ReactDOM.preload()` it will only
check if a preload exists in the Document before inserting a new one. It
should check for an underlying resource such as a stylesheet link or
script if the preload is for a recognized asset type
We used to have Event Replaying for any kind of Discrete event where
we'd track any event after hydrateRoot and before the async code/data
has loaded in to hydrate the target. However, this didn't really work
out because code inside event handlers are expected to be able to
synchronously read the state of the world at the time they're invoked.
If we replay discrete events later, the mutable state around them like
selection or form state etc. may have changed.
This limitation doesn't apply to Client Actions:
- They're expected to be async functions that themselves work
asynchronously. They're conceptually also in the "navigation" events
that happen after the "submit" events so they're already not
synchronously even before the first `await`.
- They're expected to operate mostly on the FormData as input which we
can snapshot at the time of the event.
This PR adds a bit of inline script to the Fizz runtime (or external
runtime) to track any early submit events on the page - but only if the
action URL is our placeholder `javascript:` URL. We track a queue of
these on `document.$$reactFormReplay`. Then we replay them in order as
they get hydrated and we get a handle on the Client Action function.
I add the runtime to the `bootstrapScripts` phase in Fizz which is
really technically a little too late, because on a large page, it might
take a while to get to that script even if you have displayed the form.
However, that's also true for external runtime. So there's a very short
window we might miss an event but it's good enough and better than
risking blocking display on this script.
The main thing that makes the replaying difficult to reason about is
that we can have multiple instance of React using this same queue. This
would be very usual but you could have two different Reacts SSR:ing
different parts of the tree and using around the same version. We don't
have any coordinating ids for this. We could stash something on the form
perhaps but given our current structure it's more difficult to get to
the form instance in the commit phase and a naive solution wouldn't
preserve ordering between forms.
This solution isn't 100% guaranteed to preserve ordering between
different React instances neither but should be in order within one
instance which is the common case.
The hard part is that we don't know what instance something will belong
to until it hydrates. So to solve that I keep everything in the original
queue while we wait, so that ordering is preserved until we know which
instance it'll go into. I ended up doing a bunch of clever tricks to
make this work. These could use a lot more tests than I have right now.
Another thing that's tricky is that you can update the action before
it's replayed but we actually want to invoke the old action if that
happens. So we have to extract it even if we can't invoke it right now
just so we get the one that was there during hydration.
We currently use rollup to make an adhoc bundle from the file system
when we're testing an import of an external file.
This doesn't follow all the interception rules that we use in jest and
in our actual builds.
This switches to just using jest require() to load these. This means
that they effectively have to load into the global document so this only
works with global document tests which is all we have now anyway.
This wires up, but does not yet implement, an experimental hook called
useFormStatus. The hook is imported from React DOM, not React, because
it represents DOM-specific state — its return type includes FormData as
one of its fields. Other renderers that implement similar methods would
use their own renderer-specific types.
The API is prefixed and only available in the experimental channel.
It can only be used from client (browser, SSR) components, not Server
Components.
Insert temporary input node to polyfill submitter argument in FormData.
This works for buttons too and fixes a bug where the type attribute
wasn't reset.
I also exclude the submitter if it's a function action. This ensures
that we don't include the generated "name" when the action is a server
action. Conceptually that name doesn't exist.
Fizz can emit whatever it wants for the SSR version of these fields when
it's a function action so they might not align with what is in the
previous props. Therefore we need to force them to update if we're
updating to a non-function where they might be relevant again.
Stacked on #26557
Supporting Float methods such as ReactDOM.preload() are challenging for
flight because it does not have an easy means to convey direct
executions in other environments. Because the flight wire format is a
JSON-like serialization that is expected to be rendered it currently
only describes renderable elements. We need a way to convey a function
invocation that gets run in the context of the client environment
whether that is Fizz or Fiber.
Fiber is somewhat straightforward because the HostDispatcher is always
active and we can just have the FlightClient dispatch the serialized
directive.
Fizz is much more challenging becaue the dispatcher is always scoped but
the specific request the dispatch belongs to is not readily available.
Environments that support AsyncLocalStorage (or in the future
AsyncContext) we will use this to be able to resolve directives in Fizz
to the appropriate Request. For other environments directives will be
elided. Right now this is pragmatic and non-breaking because all
directives are opportunistic and non-critical. If this changes in the
future we will need to reconsider how widespread support for async
context tracking is.
For Flight, if AsyncLocalStorage is available Float methods can be
called before and after await points and be expected to work. If
AsyncLocalStorage is not available float methods called in the sync
phase of a component render will be captured but anything after an await
point will be a noop. If a float call is dropped in this manner a DEV
warning should help you realize your code may need to be modified.
This PR also introduces a way for resources (Fizz) and hints (Flight) to
flush even if there is not active task being worked on. This will help
when Float methods are called in between async points within a function
execution but the task is blocked on the entire function finishing.
This PR also introduces deduping of Hints in Flight using the same
resource keys used in Fizz. This will help shrink payload sizes when the
same hint is attempted to emit over and over again
This is the next step toward full support for async form actions.
Errors thrown inside form actions should cause the form to re-render and
throw the error so it can be captured by an error boundary. The behavior
is the same if the `<form />` had an internal useTransition hook, which
is pretty much exactly how we implement it, too.
The first time an action is called, the form's HostComponent is
"upgraded" to become stateful, by lazily mounting a list of hooks. The
rest of the implementation for function components can be shared.
Because the error handling behavior added in this commit is just using
useTransition under-the-hood, it also handles pending states, too.
However, this pending state can't be observed until we add a new hook
for that purpose. I'll add this next.
Stacked on #26570
Previously we restricted Float methods to only being callable while
rendering. This allowed us to make associations between calls and their
position in the DOM tree, for instance hoisting preinitialized styles
into a ShadowRoot or an iframe Document.
When considering how we are going to support Flight support in Float
however it became clear that this restriction would lead to compromises
on the implementation because the Flight client does not execute within
the context of a client render. We want to be able to disaptch Float
directives coming from Flight as soon as possible and this requires
being able to call them outside of render.
this patch modifies Float so that its methods are callable anywhere. The
main consequence of this change is Float will always use the Document
the renderer script is running within as the HoistableRoot. This means
if you preinit as style inside a component render targeting a ShadowRoot
the style will load in the ownerDocument not the ShadowRoot. Practially
speaking it means that preinit is not useful inside ShadowRoots and
iframes.
This tradeoff was deemed acceptable because these methods are
optimistic, not critical. Additionally, the other methods, preconntect,
prefetchDNS, and preload, are not impacted because they already operated
at the level of the ownerDocument and really only interface with the
Network cache layer.
I added a couple additional fixes that were necessary for getting tests
to pass that are worth considering separately.
The first commit improves the diff for `waitForThrow` so it compares
strings if possible.
The second commit makes invokeGuardedCallback not use metaprogramming
pattern and swallows any novel errors produced from trying to run the
guarded callback. Swallowing may not be the best we can do but it at
least protects React against rapid failure when something causes the
dispatchEvent to throw.
In anticipation of making Fiber use the document global for dispatching
Float methods that arrive from Flight I needed to update some tests that
commonly recreated the JSDOM instance after importing react.
This change updates a few tests to only create JSDOM once per test,
before importing react-dom/client.
Additionally the current act implementation for server streaming did not
adequately model streaming semantics so I rewrite the act implementation
in a way that better mirrors how a browser would parse incoming HTML.
The new act implementation does the following
1. the first time it processes meaningful streamed content it figures
out whether it is rendering into the existing document container or if
it needs to reset the document. this is based on whether the streamed
content contains tags `<html>` or `<body>` etc...
2. Once the streaming container is set it will typically continue to
stream into that container for future calls to act. The exception is if
the streaming container is the `<head>` in which case it will switch to
streaming into the body once it receives a `<body>` tag.
This means for tests that render something like a `<div>...</div>` it
will naturally stream into the default `<div id="container">...` and for
tests that render a full document the HTML will parse like a real
browser would (with some very minor edge case differences)
I also refactored the way we move nodes from buffered content into the
document and execute any scripts we find. Previously we were using
window.eval and I switched this to just setting the external script
content as script text. Additionally the nonce logic is reworked to be a
bit simpler.
This lets you pass a function to `<form action={...}>` or `<button
formAction={...}>` or `<input type="submit formAction={...}>`. This will
behave basically like a `javascript:` URL except not quite implemented
that way. This is a convenience for the `onSubmit={e => {
e.preventDefault(); const fromData = new FormData(e.target); ... }`
pattern.
You can still implement a custom `onSubmit` handler and if it calls
`preventDefault`, it won't invoke the action, just like it would if you
used a full page form navigation or javascript urls. It behaves just
like a navigation and we might implement it with the Navigation API in
the future.
Currently this is just a synchronous function but in a follow up this
will accept async functions, handle pending states and handle errors.
This is implemented by setting `javascript:` URLs, but these only exist
to trigger an error message if something goes wrong instead of
navigating away. Like if you called `stopPropagation` to prevent React
from handling it or if you called `form.submit()` instead of
`form.requestSubmit()` which by-passes the `submit` event. If CSP is
used to ban `javascript:` urls, those will trigger errors when these
URLs are invoked which would be a different error message but it's still
there to notify the user that something went wrong in the plumbing.
Next up is improving the SSR state with action replaying and progressive
enhancement.
I accidentally made a behavior change in the refactor. It turns out that
when switching off `checked` to an uncontrolled component, we used to
revert to the concept of "initialChecked" which used to be stored on
state.
When there's a diff to this computed prop and the value of props.checked
is null, then we end up in a case where it sets `checked` to
`initialChecked`:
https://github.com/facebook/react/blob/5cbe6258bc436b1683080a6d978c27849f1d9a22/packages/react-dom-bindings/src/client/ReactDOMInput.js#L69
Since we never changed `initialChecked` and it's not relevant if
non-null `checked` changes value, the only way this "change" could
trigger was if we move from having `checked` to having null.
This wasn't really consistent with how `value` works, where we instead
leave the current value in place regardless. So this is a "bug fix" that
changes `checked` to be consistent with `value` and just leave the
current value in place. This case should already have a warning in it
regardless since it's going from controlled to uncontrolled.
Related to that, there was also another issue observed in
https://github.com/facebook/react/pull/26596#discussion_r1162295872 and
https://github.com/facebook/react/pull/26588
We need to atomically apply mutations on radio buttons. I fixed this by
setting the name to empty before doing mutations to value/checked/type
in updateInput, and then set the name to whatever it should be. Setting
the name is what ends up atomically applying the changes.
---------
Co-authored-by: Sophie Alpert <git@sophiebits.com>
Since this is an observable behavior and is hard to think about, seems
good to have tests for this.
The expected value included in each test is the behavior that existed
prior to #26546.
In
https://github.com/facebook/react/pull/26573/commits/2019ddc75f448292ffa6429d7625514af192631b,
we changed to set .defaultValue before .value on updates. In some cases,
setting .defaultValue causes .value to change, and since we only set
.value if it has the wrong value, this resulted in us not assigning to
.value, which resulted in inputValueTracking not knowing the right
value. See new test added.
My fix here is to (a) move the value setting back up first and (b)
narrowing the fix in the aforementioned PR to newly remove the value
attribute only if it defaultValue was previously present in props.
The second half is necessary because for types where the value property
and attribute are indelibly linked (hidden checkbox radio submit image
reset button, i.e. spec modes default or default/on from
https://html.spec.whatwg.org/multipage/input.html#dom-input-value-default),
we can't remove the value attribute after setting .value, because that
will undo the assignment we just did! That is, not having (b) makes all
of those types fail to handle updating props.value.
This code is incredibly hard to think about but I think this is right
(or at least, as right as the old code was) because we set .value here
only if the nextProps.value != null, and we now remove defaultValue only
if lastProps.defaultValue != null. These can't happen at the same time
because we have long warned if value and defaultValue are simultaneously
specified, and also if a component switches between controlled and
uncontrolled.
Also, it fixes the test in https://github.com/facebook/react/pull/26626.
<!--
Thanks for submitting a pull request!
We appreciate you spending the time to work on these changes. Please
provide enough information so that others can review your pull request.
The three fields below are mandatory.
Before submitting a pull request, please make sure the following is
done:
1. Fork [the repository](https://github.com/facebook/react) and create
your branch from `main`.
2. Run `yarn` in the repository root.
3. If you've fixed a bug or added code that should be tested, add tests!
4. Ensure the test suite passes (`yarn test`). Tip: `yarn test --watch
TestName` is helpful in development.
5. Run `yarn test --prod` to test in the production environment. It
supports the same options as `yarn test`.
6. If you need a debugger, run `yarn debug-test --watch TestName`, open
`chrome://inspect`, and press "Inspect".
7. Format your code with
[prettier](https://github.com/prettier/prettier) (`yarn prettier`).
8. Make sure your code lints (`yarn lint`). Tip: `yarn linc` to only
check changed files.
9. Run the [Flow](https://flowtype.org/) type checks (`yarn flow`).
10. If you haven't already, complete the CLA.
Learn more about contributing:
https://reactjs.org/docs/how-to-contribute.html
-->
## Summary
Browsers restore state like forms and scroll position right after the
popstate event. To make sure the page work as expected on back or
forward button, we need to flush transitions scheduled in a popstate
synchronously, and only yields if it suspends.
This PR adds a new HostConfig method to check if `window.event ===
'popstate'`, and `scheduleMicrotask` if a transition is scheduled in a
`PopStateEvent`.
## How did you test this change?
yarn test
Many of our Suspense-related tests were written before the `act` API was
introduced, and use the lower level `waitFor` helpers instead. So they
are less resilient to changes in implementation details than they could
be.
This converts some of our test suite to use `act` in more places. I
found these while working on a PR to expand our fallback throttling
mechanism to include all renders that result from a promise resolving,
even if there are no more fallbacks in the tree.
I think this covers all the remaining tests that are affected.
This traces back to https://github.com/facebook/react/pull/6449 and then
another before that.
I think that back then we favored the property over the attribute, and
setting the property wouldn't be enough. However, the default path for
these are now using attributes if we don't special case it. So we don't
need it.
The only difference is that we currently have a divergence for
symbol/function behavior between controlled values that use the
getToStringValue helpers which treat them as empty string, where as
everywhere else they're treated as null/missing.
Since this comes with a warning and is a weird error case, it's probably
fine to change.
part of https://github.com/facebook/react/pull/26571
merging separately to improve tracking of files renames in git
Rename HostConfig files to FiberConfig to clarify they are configs for
Fiber and not Fizz/Flight. This better conforms to the naming used in
Flight and now Fizz of `ReactFlightServerConfig` and `ReactFizzConfig`
In #26573 I changed it so that textareas get their defaultValue reset if
you don't specify one.
However, the way that was implemented, it always set it for any update
even if it hasn't changed.
We have a test for that, but that test only works if no properties
update at all so that no update was scheduled. This fixes the test so
that it updates some unrelated prop.
I also found a test for `checked` that needed a similar fix.
Interestingly, we don't do this deduping for `defaultValue` or
`defaultChecked` on inputs and there's no test for that.
This is mainly renaming some stuff. The behavior change is
hasOwnProperty to nullish check.
I had a bigger refactor that was a dead-end but might as well land this
part and see if I can pick it up later.
There are four places we have special cases based off the DOMProperty
config:
1) DEV-only: ReactDOMUnknownPropertyHook warns for passing booleans to
non-boolean attributes. We just need a simple list of all properties
that are affected by that. We could probably move this in under setProp
instead and have it covered by that list.
2) DEV-only: Hydration. This just needs to read the value from an
attribute and compare it to what we'd expect to see if it was rendered
on the client. This could use some simplification/unification of the
code but I decided to just keep it simple and duplicated since code size
isn't an issue.
3) DOMServerFormatConfig pushAttribute: This just maps the special case
to how to emit it as a HTML attribute.
4) ReactDOMComponent setProp: This just maps the special case to how to
emit it as setAttribute or removeAttribute.
Basically we just have to remember to keep pushAttribute and setProp
aligned. There's only one long switch in prod per environment.
This just turns it all to a giant simple switch statement with string
cases. This is in theory the most optimizable since syntactically all
the information for a hash table is there. However, unfortunately we
know that most VMs don't optimize this very well and instead just turn
them into a bunch of ifs. JSC is best. We can minimize the cost by just
moving common attribute to the beginning of the list.
If we shipped this, maybe VMs will get it together to start optimizing
this case but there's a chicken and egg problem here and the game theory
reality is that we probably don't want to regress. Therefore, I intend
to do a follow up after landing this which reintroduces an object
indirection for simple property aliases. That should be enough to make
the remaining cases palatable. I'll also extract the most common
attributes to the beginning or separate ifs.
Ran attribute-behavior fixture and the table is the same.
This reverts commit b2ae9ddb3b.
While the feature flag is fully rolled out, these tests are also testing
behavior set with an unstable flag on root, which for now we want to
preserve.
Not sure if there's a better way then adding a dynamic feature flag to
the www build?
We almost never want to show content before its styles have loaded. But
eventually we will give up and allow unstyled content. So this extends
the timeout to a full minute. This somewhat arbitrary — big enough that
you'd only reach it under extreme circumstances.
Note that, like regular Suspense, the app is still interactive while
we're waiting for content to load. Only the unstyled content is blocked
from appearing, not updates in general. A new update will interrupt it.
We should figure out what the browser engines do during initial page
load and consider aligning our behavior with that. It's supposed to be
render blocking by default but there may be some cases where they, too,
give up and FOUC.
I originally made it so that a Suspensey commit — i.e. a commit that's
waiting for a stylesheet, image, or font to load before proceeding —
could not be interrupted by transitions. My reasoning was that Suspensey
commits always time out after a short interval, anyway, so if the
incoming update isn't urgent, it's better to wait to commit the current
frame instead of throwing it away.
I don't think this rationale was correct, for a few reasons. There are
some cases where we'll suspend for a longer duration, like stylesheets —
it's nearly always a bad idea to show content before its styles have
loaded, so we're going to be extend this timeout to be really long.
But even in the case where the timeout is shorter, like fonts, if you
get a new update, it's possible (even likely) that update will allow us
to avoid showing a fallback, like by navigating to a different page. So
we might as well try.
The behavior now matches our behavior for interrupting a suspended
render phase (i.e. `use`), which makes sense because they're not that
conceptually different.
This flag is already enabled everywhere except for www, which is blocked
by a few tests that assert on the old behavior. Once www is ready, I'll
land this.
This PR has a bunch of surrounding refactoring. See individual commits.
The main change is that we no longer special case `typeof is ===
'string'` as a special case according to the
`enableCustomElementPropertySupport` flag.
Effectively this means that you can't use custom properties/events,
other than the ones React knows about on `<input is="my-input">`
extensions.
This is unfortunate but there's too many paths that are forked in
inconsistent ways since we fork based on tag name. I think __the
solution is to let all React elements set unknown properties/events in
the same way as this flag__ but that's a bigger change than this flag
implies.
Since `is` is not universally supported yet anyway, this doesn't seem
like a huge loss. Attributes still work.
We still support passing the `is` prop and turn that into the
appropriate createElement call.
@josepharhar
This is a step towards getting rid of the meta programming in
DOMProperty and CSSProperty.
This moves isAttributeNameSafe and isUnitlessNumber to a separate shared
modules.
isUnitlessNumber is now a single switch instead of meta-programming.
There is a slight behavior change here in that I hard code a specific
set of vendor-prefixed attributes instead of prefixing all the unitless
properties. I based this list on what getComputedStyle returns in
current browsers. I removed Opera prefixes because they were [removed in
Opera](https://dev.opera.com/blog/css-vendor-prefixes-in-opera-12-50-snapshots/)
itself. I included the ms ones mentioned [in the original
PR](https://github.com/facebook/react/commit/5abcce534382d85887f3d33475e8e54e3b5d8457).
These shouldn't really be used anymore anyway so should be pretty safe.
Worst case, they'll fallback to the other property if you specify both.
Finally I inline the mustUseProperty special cases - which are also the
only thing that uses propertyName. These are really all controlled
components and all booleans.
I'm making a small breaking change here by treating `checked` and
`selected` specially only on the `input` and `option` tags instead of
all tags. That's because those are the only DOM nodes that actually have
those properties but we used to set them as expandos instead of
attributes before. That's why one of the tests is updated to now use
`input` instead of testing an expando on a `div` which isn't a real use
case. Interestingly this also uncovered that we update checked twice for
some reason but keeping that logic for now.
Ideally `multiple` and `muted` should move into `select` and
`audio`/`video` respectively for the same reason.
No change to the attribute-behavior fixture.
Josh Story
Ricky
Sebastian Markbåge
Yen-Wei Liu
Dennis Moradkhani
Sophie Alpert
Andrew Clark
Dan Ott
Tianyu Yao
Jan Kassens