**what is the change?:**
Test coverage checking that callbacks are called when they time out.
This test surfaced a bug and this commit includes the fix.
I want to refine this approach, but basically we can simulate time outs
by controlling the return value of 'now()' and the argument passed to
the rAF callback.
Next we will write a browser fixture to further test this against real
browser APIs.
**why make this change?:**
Better tests will keep this module working smoothly while we continue
refactoring and improving it.
**test plan:**
Run the new tests, see that it fails without the bug fix.
* 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
**what is the change?:**
Fix a typo which caused timed out callbacks to not be called.
**why make this change?:**
This is a bug caught by tests I'm in the process of writing, and we
should fix it asap.
**test plan:**
Tests in a WIP PR - will push and share the WIP test in comments on this
PR.
* Temporary fix for grabbing wrong rAF polyfill in ReactScheduler
**what is the change?:**
For now...
We need to grab a slightly different implementation of rAF internally at
FB than in Open Source. Making rAF a dependency of the ReactScheduler
module allows us to fork the dependency at FB.
NOTE: After this lands we have an alternative plan to make this module
separate from React and require it before our Facebook timer polyfills
are applied. But want to land this now to keep master in a working state
and fix bugs folks are seeing at Facebook.
Thanks @sebmarkbage @acdlite and @sophiebits for discussing the options
and trade-offs for solving this issue.
**why make this change?:**
This fixes a problem we're running into when experimenting with
ReactScheduler internally at Facebook, **and* it's part of our long term
plan to use dependency injection with the scheduler to make it easier to
test and adjust.
**test plan:**
Ran tests, lint, flow, and will manually test when syncing into
Facebook's codebase.
**issue:**
See internal task T29442940
* ran prettier
**what is the change?:**
We were setting a flag after some early returns, should have set it
right away.
To be fair, it's not clear how you can hit a problem with the current
state of things. Even if a callback is cancelled, it's still in the
'pendingCallbacks' queue until the rAF runs, and we only schedule a rAF
when there are pendingCallbacks in the queue.
But since this is obviously wrong, going to fix it.
We will be adding a regression test in a follow-up PR.
**why make this change?:**
To fix a random bug which was popping up.
**test plan:**
Adding a regression unit test in a follow-up PR.
**what is the change?:**
In some cases we had defined the 'callback' as taking two arguments,
when really we meant to indicate the second argument passed to
'scheduleWork'.
**why make this change?:**
For correctness and to unblock something @gaearon is working on. A bit
surprised Flow didn't catch this in the first place.
**test plan:**
Ran tests, flow, lint.
* 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
* Support using id to cancel scheduled callback
**what is the change?:**
see title
**why make this change?:**
Once we support multiple callbacks you will need to use the id to
specify which callback you mean.
**test plan:**
Added a test, ran all tests, lint, etc.
* ran prettier
* fix lint
* Use object for storing callback info in scheduler
* Wrap initial test in a describe block
* Support multiple callbacks in `ReactScheduler`
**what is the change?:**
We keep a queue of callbacks instead of just one at a time, and call
them in order first by their timeoutTime and then by the order which
they were scheduled in.
**why make this change?:**
We plan on using this module to coordinate JS outside of React, so we
will need to schedule more than one callback at a time.
**test plan:**
Added a boatload of shiny new tests. :)
Plus ran all the old ones.
NOTE: The tests do not yet cover the vital logic of callbacks timing
out, and later commits will add the missing test coverage.
* Heuristic to avoid looking for timed out callbacks when none timed out
**what is the change?:**
Tracks the current soonest timeOut time for all scheduled callbacks.
**why make this change?:**
We were checking every scheduled callback to see if it timed out on
every tick. It's more efficient to skip that O(n) check if we know that
none have timed out.
**test plan:**
Ran existing tests.
Will write new tests to cover timeout behavior in more detail soon.
* Put multiple callback support under a disabled feature flag
**what is the change?:**
See title
**why make this change?:**
We don't have error handling in place yet, so should maintain the old
behavior until that is in place.
But want to get this far to continue making incremental changes.
**test plan:**
Updated and ran tests.
* Hide support for multiple callbacks under a feature flag
**what is the change?:**
see title
**why make this change?:**
We haven't added error handling yet, so should not expose this feature.
**test plan:**
Ran all tests, temporarily split out the tests for multiple callbacks
into separate file. Will recombine once we remove the flag.
* Fix nits from code review
See comments on https://github.com/facebook/react/pull/12743
* update checklist in comments
* Remove nested loop which calls additional timed out callbacks
**what is the change?:**
We used to re-run any callbacks which time out whilst other callbacks
are running, but now we will only check once for timed out callbacks
then then run them.
**why make this change?:**
To simplify the code and the behavior of this module.
**test plan:**
Ran all existing tests.
* Remove feature flag
**what is the change?:**
see title
**why make this change?:**
Because only React is using this, and it sounds like async. rendering
won't hit any different behavior due to these changes.
**test plan:**
Existing tests pass, and this allowed us to recombine all tests to run
in both 'test' and 'test-build' modes.
* remove outdated file
* fix typo
**what is the change?:**
We had a condition to set either 'performance.now' or 'Date.now' as the
'now' function.
Then later we had another conditional checking again if
'performance.now' was supported, and using it if so, otherwise falling
back to 'Date.now'.
More efficient to just use the 'now' shortcut defined above.
**why make this change?:**
Fewer lines, clearer code.
**test plan:**
Now that we have tests we can run them :)
* Remove the 'alwaysUseRequestIdleCallbackPolyfill' feature flag
**what is the change?:**
Removes the feature flag 'alwaysUseRequestIdleCallbackPolyfill', such
that we **always** use the polyfill for requestIdleCallback.
**why make this change?:**
We have been testing this feature flag at 100% for some time internally,
and determined it works better for React than the native implementation.
Looks like RN was overriding the flag to use the native when possible,
but since no RN products are using 'async' mode it should be safe to
switch this flag over for RN as well.
**test plan:**
We have already been testing this internally for some time.
**issue:**
internal task t28128480
* fix mistaken conditional
* Add mocking of rAF, postMessage, and initial test for ReactScheduler
**what is the change?:**
- In all tests where we previously mocked rIC or relied on native
mocking which no longer works, we are now mocking rAF and postMessage.
- Also adds a basic initial test for ReactScheduler.
NOTE -> we do plan to write headless browser tests for ReactScheduler!
This is just an initial test, to verify that it works with the mocked
out browser APIs as expected.
**why make this change?:**
We need to mock out the browser APIs more completely for the new
'ReactScheduler' to work in our tests. Many tests are depending on it,
since it's used at a low level.
By mocking the browser APIs rather than the 'react-scheduler' module, we
enable testing the production bundles. This approach is trading
isolation for accuracy. These tests will be closer to a real use.
**test plan:**
run the tests :)
**issue:**
internal task T28128480
This is the first step - pulling the ReactDOMFrameScheduling module out
into a separate package.
Co-authored-by: Brandon Dail <aweary@users.noreply.github.com>
Flarnie Marchan
Dan Abramov
Royi Hagigi
Andrew Clark
