Fixes#13777
As part of #11927 we introduced a regression by adding onclick handler
to the React root. This causes the whole React tree to flash when tapped
on iOS devices (for reasons I outlined in
https://github.com/facebook/react/issues/12989#issuecomment-414266839).
To fix this, we should only apply onclick listeners to portal roots. I
verified that my proposed fix indeed works by checking out our DOM
fixtures and adding regression tests.
Strangely, I had to make changes to the DOM fixtures to see the behavior
in the first place. This seems to be caused by our normal sites (and
thus their React root) being bigger than the viewport:

An alternative approach to finding out if we're appending to a React
root would be to add a third parameter to `appendChildToContainer` based
on the tag of the parent fiber.
All of these features are based on features of React's internal
scheduler. The eventual goal is to lift as much as possible out of the
React internals into the Scheduler package.
Includes some renaming of existing methods.
- `scheduleWork` is now `scheduleCallback`
- `cancelScheduledWork` is now `cancelCallback`
Priority levels
---------------
Adds the ability to schedule callbacks at different priority levels.
The current levels are (final names TBD):
- Immediate priority. Fires at the end of the outermost currently
executing (similar to a microtask).
- Interactive priority. Fires within a few hundred milliseconds. This
should only be used to provide quick feedback to the user as a result
of an interaction.
- Normal priority. This is the default. Fires within several seconds.
- "Maybe" priority. Only fires if there's nothing else to do. Used for
prerendering or warming a cache.
The priority is changed using `runWithPriority`:
```js
runWithPriority(InteractivePriority, () => {
scheduleCallback(callback);
});
```
Continuations
-------------
Adds the ability for a callback to yield without losing its place
in the queue, by returning a continuation. The continuation will have
the same expiration as the callback that yielded.
Wrapped callbacks
-----------------
Adds the ability to wrap a callback so that, when it is called, it
receives the priority of the current execution context.
* Merged interaction-tracking package into react-scheduler
* Add tracking API to FB+www builds
* Added Rollup plugin to strip no-side-effect imports from Rollup bundles
* Re-bundle tracking and scheduling APIs on SECRET_INTERNALS object for UMD build (and provide lazy forwarding methods)
* Added some additional tests and fixtures
* Fixed broken UMD fixture in master (#13512)
* Replace some namespace imports
* Simplify the controlled component injection
* Simplify the batching injection
* Simplify the component tree injection
* Make option children a text content by default
fix#11911
* Apply requested changes
- Remove meaningless comments
- revert scripts/rollup/results.json
* remove empty row
* Update comment
* Add a simple unit-test
* [WIP: no flow] Pass through hostContext
* [WIP: no flow] Give better description for test
* Fixes
* Don't pass hostContext through
It ended up being more complicated than I thought.
* Also warn on hydration
* Prepare placeholders before timing out
While a tree is suspended, prepare for the timeout by pre-rendering the
placeholder state.
This simplifies the implementation a bit because every render now
results in a completed tree.
* Suspend inside an already timed out Placeholder
A component should be able to suspend inside an already timed out
placeholder. The time at which the placeholder committed is used as
the start time for a subsequent suspend.
So, if a placeholder times out after 3 seconds, and an inner
placeholder has a threshold of 2 seconds, the inner placeholder will
not time out until 5 seconds total have elapsed.
* Use local references to global things inside 'scheduler'
**what is the change?:**
See title
**why make this change?:**
We want to avoid initially calling one version of an API and then later
accessing a polyfilled version.
**test plan:**
Run existing tests.
* Shim ReactScheduler for www
**what is the change?:**
In 'www' we want to reference the separate build of ReactScheduler,
which allows treating it as a separate module internally.
**why make this change?:**
We need to require the ReactScheduler before our rAF polyfill activates,
in order to customize which custom behaviors we want.
This is also a step towards being able to experiment with using it
outside of React.
**test plan:**
Ran tests, ran the build, and ran `test-build`.
* Generate a bundle for fb-www
**what is the change?:**
See title
**why make this change?:**
Splitting out the 'schedule' module allows us to load it before
polyfills kick in for rAF and other APIs.
And long term we want to split this into a separate module anyway, this
is a step towards that.
**test plan:**
I'll run the sync next week and verify that this all works. :)
* ran prettier
* fix rebase issues
* Change names of variables used for holding globals
* Extract base Jest config
This makes it easier to change the source config without affecting the build test config.
* Statically import the host config
This changes react-reconciler to import HostConfig instead of getting it through a function argument.
Rather than start with packages like ReactDOM that want to inline it, I started with React Noop and ensured that *custom* renderers using react-reconciler package still work. To do this, I'm making HostConfig module in the reconciler look at a global variable by default (which, in case of the react-reconciler npm package, ends up being the host config argument in the top-level scope).
This is still very broken.
* Add scaffolding for importing an inlined renderer
* Fix the build
* ES exports for renderer methods
* ES modules for host configs
* Remove closures from the reconciler
* Check each renderer's config with Flow
* Fix uncovered Flow issue
We know nextHydratableInstance doesn't get mutated inside this function, but Flow doesn't so it thinks it may be null.
Help Flow.
* Prettier
* Get rid of enable*Reconciler flags
They are not as useful anymore because for almost all cases (except third party renderers) we *know* whether it supports mutation or persistence.
This refactoring means react-reconciler and react-reconciler/persistent third-party packages now ship the same thing.
Not ideal, but this seems worth how simpler the code becomes. We can later look into addressing it by having a single toggle instead.
* Prettier again
* Fix Flow config creation issue
* Fix imprecise Flow typing
* Revert accidental changes
* Rename Scheduler methods more accurately
**what is the change?:**
```
rIC -> scheduleCallback
```
We will later expose a second method for different priority level, name
TBD. Since we only have one priority right now we can delay the
bikeshedding about the priority names.
cIC -> cancelScheduledCallback
This method can be used to cancel callbacks scheduled at any priority
level, and will remain named this way.
why make this change?:
Originally this module contained a polyfill for requestIdleCallback
and cancelIdleCallback but we are changing the behavior so it's no
longer just a polyfill. The new names are more semantic and distinguish
this from the original polyfill functionality.
**test plan:**
Ran the tests
**why make this change?:**
Getting this out of the way so things are more clear.
**Coming Up Next:**
- Switching from a Map of ids and an array to a linked list for storing
callbacks.
- Error handling
* callback -> work
* update callsites in new places after rebase
* fix typo