Commit Graph

160 Commits

Author SHA1 Message Date
Andrew Clark
4d9f850065 Re-throw errors thrown by the renderer at the root in the complete phase (#18029)
* Re-throw errors thrown by the renderer at the root

React treats errors thrown at the root as a fatal because there's no
parent component that can capture it. (This is distinct from an
"uncaught error" that isn't wrapped in an error boundary, because in
that case we can fall back to deleting the whole tree -- not great, but
at least the error is contained to a single root, and React is left in a
consistent state.)

It turns out we didn't have a test case for this path. The only way it
can happen is if the renderer's host config throws. We had similar test
cases for host components, but none for the host root.

This adds a new test case and fixes a bug where React would keep
retrying the root because the `workInProgress` pointer was not advanced
to the next fiber. (Which in this case is `null`, since it's the root.)

We could consider in the future trying to gracefully exit from certain
types of root errors without leaving React in an inconsistent state. For
example, we should be able to gracefully exit from errors thrown in the
begin phase. For now, I'm treating it like an internal invariant and
immediately exiting.

* Add comment
2020-02-18 15:55:38 -08:00
Sunil Pai
3e9251d605 make testing builds for React/ReactDOM (#17915)
This PR introduces adds `react/testing` and `react-dom/testing`.
- changes infra to generate these builds
- exports act on ReactDOM in these testing builds
- uses the new test builds in fixtures/dom

In the next PR -

- I'll use the new builds for all our own tests
- I'll replace usages of TestUtils.act with ReactDOM.act.
2020-02-03 23:31:31 +00:00
Dominic Gannaway
434770c3b4 Add beforeRemoveInstance method to ReactNoop (#17959) 2020-02-03 11:31:51 +00:00
Dan Abramov
e706721490 Update Flow to 0.84 (#17805)
* Update Flow to 0.84

* Fix violations

* Use inexact object syntax in files from fbsource

* Fix warning extraction to use a modern parser

* Codemod inexact objects to new syntax

* Tighten types that can be exact

* Revert unintentional formatting changes from codemod
2020-01-09 14:50:44 +00:00
Dominic Gannaway
9fe1031244 [react-interactions] Rename Flare APIs to deprecated and remove from RN (#17644) 2019-12-18 10:24:46 +00:00
Dan Abramov
0cf22a56a1 Use console directly instead of warning() modules (#17599)
* Replace all warning/lowPriWarning with console calls

* Replace console.warn/error with a custom wrapper at build time

* Fail the build for console.error/warn() where we can't read the stack
2019-12-14 18:09:25 +00:00
Dan Abramov
b15bf36750 Add component stacks to (almost) all warnings (#17586) 2019-12-12 23:47:55 +00:00
Laura buns
9ac42dd074 Remove the condition argument from warning() (#17568)
* prep for codemod

* prep warnings

* rename lint rules

* codemod for ifs

* shim www functions

* Handle more cases in the transform

* Thanks De Morgan

* Run the codemod

* Delete the transform

* Fix up confusing conditions manually

* Fix up www shims to match expected API

* Also check for low-pri warning in the lint rule
2019-12-11 03:28:14 +00:00
Andrew Clark
7bf40e1cfd Initialize update queue object on mount (#17560)
* Refactor Update Queues to Fix Rebasing Bug

Fixes a bug related to rebasing updates. Once an update has committed,
it should never un-commit, even if interrupted by a higher priority
update. The fix includes a refactor of how update queues work.

This commit is a combination of two PRs:

- #17483 by @sebmarkbage refactors the hook update queue
- #17510 by @acdlite refactors the class and root update queue

Landing one without the other would cause state updates to sometimes be
inconsistent across components, so I've combined them into a single
commit in case they need to be reverted.

Co-authored-by: Sebastian Markbåge <sema@fb.com>
Co-authored-by: Andrew Clark <git@andrewclark.io>

* Initialize update queue object on mount

Instead of lazily initializing update queue objects on the first update,
class and host root queues are created on mount. This simplifies the
logic for appending new updates and matches what we do for hooks.
2019-12-10 18:42:42 -06:00
Andrew Clark
e039e690b5 Revert Update Queue Refactor
Reverts b617db3d96.

Found some bugs when attempting to land in www. Reverting to fix master.
I'll land again *after* the change successfully land downstream.
2019-12-09 15:16:09 -08:00
Andrew Clark
b617db3d96 Refactor Update Queues to Fix Rebasing Bug
Fixes a bug related to rebasing updates. Once an update has committed,
it should never un-commit, even if interrupted by a higher priority
update. The fix includes a refactor of how update queues work.

This commit is a combination of two PRs:

- #17483 by @sebmarkbage refactors the hook update queue
- #17510 by @acdlite refactors the class and root update queue

Landing one without the other would cause state updates to sometimes be
inconsistent across components, so I've combined them into a single
commit in case they need to be reverted.

Co-authored-by: Sebastian Markbåge <sema@fb.com>
Co-authored-by: Andrew Clark <git@andrewclark.io>
2019-12-09 13:19:26 -08:00
Dan Abramov
b8f8258775 Split ReactDOM entry point (#17331)
* Split ReactDOM entry point

* BatchedRoot -> BlockingRoot
2019-11-10 13:43:29 +00:00
Sebastian Markbåge
f4148b2561 [Flight] Move around the Server side a bit (#17251)
* Rename ReactFlightStreamer -> ReactFlightServer

* Unify Browser/Node stream tests into one file and use the client reader

* Defer to the actual ReactDOM for HTML rendering for now

This will need to use a variant of Fizz to do inline SSR in Flight.
However, I don't want to build the whole impl right now but also don't
want to exclude the use case yet. So I outsource it to the existing
renderer. Ofc, this doesn't work with Suspense atm.
2019-11-01 17:39:24 -07:00
Sebastian Markbåge
fadc97167f [Flight] Add Client Infrastructure (#17234)
* Change demo to server

* Expose client in package.json

* Reorganize tests

We don't want unit tests but instead test how both server and clients work
together. So this merges server/client test files.

* Fill in the client implementation a bit

* Use new client in fixture

* Add Promise/Uint8Array to lint rule

I'll probably end up deleting these deps later but they're here for now.
2019-11-01 16:05:07 -07:00
Sebastian Markbåge
f4e974d26e Add Experimental Flight Infrastructure (#16398)
* Add Flight Build and Unify HostFormat Config between Flight and Fizz

* Add basic resolution of models

* Add basic Flight fixture

Demonstrates the streaming protocol.

* Rename to flight-server to distinguish from the client parts

* Add Flight Client package and entry point

* Fix fixture
2019-10-29 14:45:47 -07:00
Dan Abramov
f6b8d31a76 Rename createSyncRoot to createBlockingRoot (#17165)
* Rename createSyncRoot to createBlockingRoot

* Fix up
2019-10-23 15:04:39 -07:00
Dominic Gannaway
b71ab61c8f [react-interactions] Adds more experimental Scope API methods (#17042) 2019-10-08 19:32:53 +02:00
Andrew Clark
71d012ecd0 Remove dormant createBatch experiment (#17035)
* Remove dormant createBatch experiment

In a hybrid React app with multiple roots, `createBatch` is used to
coordinate an update to a root with its imperative container.

We've pivoted away from multi-root, hybrid React apps for now to focus
on single root apps.

This PR removes the API from the codebase. It's possible we'll add back
some version of this feature in the future.

* Remove unused export
2019-10-07 14:15:15 -07:00
Sebastian Markbåge
c80678c760 Add "hydrationOptions" behind the enableSuspenseCallback flag (#16434)
This gets invoked when a boundary is either hydrated or if it is deleted
because it updated or got deleted before it mounted.
2019-08-19 13:26:39 -07:00
Sunil Pai
a1dbb852c2 warn if you try to use act() in prod (#16282)
We have behaviour divergence for act() between prod and dev (specifically, act() + concurrent mode does not flush fallbacks in prod. This doesn't affect anyone in OSS yet)

We also don't have a good story for writing tests in prod (and what from what I gather, nobody really writes tests in prod mode).

We could have wiped out act() in prod builds, except that _we_ ourselves use act() for our tests when we run them in prod mode.

This PR is a compromise to all of this. We will log a warning if you try to use act() in prod mode, and we silence it in our test suites.
2019-08-05 13:01:05 -07:00
Sunil Pai
e6a0473c3c Warn when rendering tests in concurrent/batched mode without a mocked scheduler (#16207)
Concurrent/Batched mode tests should always be run with a mocked scheduler (v17 or not). This PR adds a warning for the same. I'll put up a separate PR to the docs with a page detailing how to mock the scheduler.
2019-07-30 19:00:18 +01:00
Sunil Pai
d412eec839 [act] flush work correctly without a mocked scheduler (#16223)
Not returning the value of flushPassiveEffects() in flushWork() meant that with async act, we wouldn't flush all work with cascading effects. This PR fixes that oversight, and adds some tests to catch this in the future.
2019-07-26 17:48:42 +01:00
Sunil Pai
c73e1f236f flush work on exiting outermost act(), with nested act()s from different renderers (#16181)
Given this snippet:
```jsx
    TestRenderer.act(() => {
      TestUtils.act(() => {
        TestRenderer.create(<Effecty />);
      });
    });
```
We want to make sure that all work is only flushed on exiting the outermost act().

Now, naively doing this based on actingScopeDepth would work with a mocked scheduler, where flushAll() would flush all work across renderers.

This doesn't work without mocking the scheduler though; and where flushing work only works per renderer. So we disable this behaviour for a non-mocked scenario. This seems like an ok tradeoff.
2019-07-24 00:20:28 +01:00
Dominic Gannaway
5098891193 [Flare] Redesign core event system (#16163) 2019-07-23 23:46:44 +01:00
Dominic Gannaway
2c4d61e102 Adds experimental fundamental interface (#16049) 2019-07-19 22:20:28 +01:00
Sunil Pai
b8f91e6649 [fail] reset IsThisRendererActing correctly (#16042)
* [fail] reset IsThisRendererActing correctly

I missed this in https://github.com/facebook/react/pull/16039. I'd pointed at the wrong previous state, corrupting it in further use. This PR fixes that, and adds a test to make sure it doesn't happen again.

* warn for unacted effects only in strict mode
2019-07-03 03:04:22 +01:00
Sunil Pai
a457e02ae3 allow nested act()s from different renderers (#16039)
* allow nested `act()`s from different renderers

There are usecases where multiple renderers need to oprate inside an act() scope
- ReactDOM.render being used inside another component tree. The parent component will be rendered using ReactTestRenderer.create for a snapshot test or something.
- a ReactDOM instance interacting with a ReactTestRenderer instance (like for the new devtools)

This PR changes the way the acting sigils operate to allow for this. It keeps 2 booleans, one attached to React, one attached to the renderer. act() changes these values, and the workloop reads them to decide what warning to trigger.

I also renamed shouldWarnUnactedUpdates to warnsIfNotActing

* s/ReactIsActing/IsSomeRendererActing and s/ReactRendererIsActing/IsThisRendererActing
2019-07-02 22:20:17 +01:00
Dominic Gannaway
9b0bd43550 [Flare] Re-label Flare flag (#16014) 2019-06-28 01:11:11 +01:00
Dominic Gannaway
8b88ac2592 [Flare] Remove event targets including TouchHitTarget (#16011) 2019-06-27 23:58:48 +01:00
Andrew Clark
4d307de458 Prefix mock Scheduler APIs with _unstable (#15999)
For now this is only meant to be consumed via `act`.
2019-06-26 12:16:08 -07:00
Sunil Pai
fce15f14d3 don't fire missing act() warnings for react-art (#15975)
* use toWarnDev for dom fixture tests

forks toWarnDev from root into fixture/dom, updates tes tests to use it

* disable act() warnings for react-art()

- For 'secondary' renderers like react-act, we don't want to fire missing act() warnings; the wrapping renderer will fire warnings anyway, and when it flushes, it flushes effects *across* renderers.

- I could have used isPrimaryRenderer as the flag, but this is marked as false for react-test-renderer, and we *do* want the warning to fire for it. Hence a new flag.

* add missing dependency `art` to fixtures/dom
2019-06-24 19:18:26 +01:00
Sunil Pai
ff91bfa58c [act] reset scope depth on synchronous errors (#15937)
* reset scope depth on synchronous errors

we weren't resetting the acting scope depth on sync errors thrown in the callback. this fixes that.

* typos

* add a test to make sure sync error propagate
2019-06-20 13:50:53 +01:00
Sunil Pai
9aad17d60c using the wrong renderer's act() should warn (#15756)
* warn when using the wrong renderer's act around another renderer's updates

like it says. it uses a real object as the sigil (instead of just a boolean). specifically, it uses a renderer's flushPassiveEffects as the sigil. We also run tests for this separate from our main suite (which doesn't allow loading multiple renderers in a suite), but makes sure to run this in CI as well.

* unneeded (and wrong) comment

* run the dom fixture on CI

* update the sigil only in __DEV__

* remove the obnoxious comment

* use an explicit export for the sigil
2019-05-29 22:56:04 +01:00
Andrew Clark
d915a4c1f1 [Suspense] Add Batched Mode variant to fuzz tester (#15734) 2019-05-28 11:41:01 -07:00
Sebastian Markbåge
8af1f87929 Rename ReactFiberScheduler -> ReactFiberWorkLoop and extract throwException from Unwind (#15725)
* Rename ReactFiberScheduler to ReactFiberWorkLoop

The scheduling part is mostly extracted out to the scheduler package.

What's remaining is mostly around the loop around each section of work.
I name it something with Work in it because it's very related to the
BeginWork, CompleteWork and UnwindWork sections.

* Extract throwException from UnwindWork

Our throwing works more like algebraic effects in that it's a separate
phase where we find a handler and we later unwind.
2019-05-23 14:24:18 -07:00
Dominic Gannaway
ef4ac42f88 [Flare] Update interactiveUpdates flushing heuristics (#15687) 2019-05-21 22:03:45 +01:00
Sunil Pai
9c9ea94852 flush only on exiting outermost act() (#15682) 2019-05-21 10:41:24 +01:00
Sunil Pai
d278a3ff8b act() - s / flushPassiveEffects / Scheduler.unstable_flushWithoutYielding (#15591)
* s/flushPassiveEffects/unstable_flushWithoutYielding

a first crack at flushing the scheduler manually from inside act(). uses unstable_flushWithoutYielding(). The tests that changed, mostly replaced toFlushAndYield(...) with toHaveYielded(). For some tests that tested the state of the tree before flushing effects (but still after updates), I replaced act() with bacthedUpdates().

* ugh lint

* pass build, flushPassiveEffects returns nothing now

* pass test-fire

* flush all work (not just effects), add a compatibility mode

of note, unstable_flushWithoutYielding now returns a boolean much like flushPassiveEffects

* umd build for scheduler/unstable_mock, pass the fixture with it

* add a comment to Shcduler.umd.js for why we're exporting unstable_flushWithoutYielding

* run testsutilsact tests in both sync/concurrent modes

* augh lint

* use a feature flag for the missing mock scheduler warning

I also tried writing a test for it, but couldn't get the scheduler to unmock. included the failing test.

* Update ReactTestUtilsAct-test.js

- pass the mock scheduler warning test,
- rewrite some tests to use Scheduler.yieldValue
- structure concurrent/legacy suites neatly

* pass failing tests in batchedmode-test

* fix pretty/lint/import errors

* pass test-build

* nit: pull .create(null) out of the act() call
2019-05-16 17:12:36 +01:00
Andrew Clark
862f499fac Add Batched Mode (#15502)
* Add Batched Mode

React has an unfortunate quirk where updates are sometimes synchronous
-- where React starts rendering immediately within the call stack of
`setState` — and sometimes batched, where updates are flushed at the
end of the current event. Any update that originates within the call
stack of the React event system is batched. This encompasses most
updates, since most updates originate from an event handler like
`onClick` or `onChange`. It also includes updates triggered by lifecycle
methods or effects. But there are also updates that originate outside
React's event system, like timer events, network events, and microtasks
(promise resolution handlers). These are not batched, which results in
both worse performance (multiple render passes instead of single one)
and confusing semantics.

Ideally all updates would be batched by default. Unfortunately, it's
easy for components to accidentally rely on this behavior, so changing
it could break existing apps in subtle ways.

One way to move to a batched-by-default model is to opt into Concurrent
Mode (still experimental). But Concurrent Mode introduces additional
semantic changes that apps may not be ready to adopt.

This commit introduces an additional mode called Batched Mode. Batched
Mode enables a batched-by-default model that defers all updates to the
next React event. Once it begins rendering, React will not yield to
the browser until the entire render is finished.

Batched Mode is superset of Strict Mode. It fires all the same warnings.
It also drops the forked Suspense behavior used by Legacy Mode, in favor
of the proper semantics used by Concurrent Mode.

I have not added any public APIs that expose the new mode yet. I'll do
that in subsequent commits.

* Suspense in Batched Mode

Should have same semantics as Concurrent Mode.

* Use RootTag field to configure type of root

There are three types of roots: Legacy, Batched, and Concurrent.

* flushSync should not flush batched work

Treat Sync and Batched expiration times separately. Only Sync updates
are pushed to our internal queue of synchronous callbacks.

Renamed `flushImmediateQueue` to `flushSyncCallbackQueue` for clarity.
2019-05-13 14:30:39 -07:00
Dominic Gannaway
aece8119cf Refactor EventComponent logic + add onOwnershipChange callback (#15354) 2019-04-09 12:47:32 +01:00
Dominic Gannaway
4064ea9fa6 Experimental event API: Support EventComponent onUnmount responder callback (#15335) 2019-04-06 08:16:57 +01:00
Dominic Gannaway
4fbbae8afa Add full TouchHitTarget hit slop (experimental event API) to ReactDOM (#15308) 2019-04-06 07:51:21 +01:00
Sunil Pai
aed0e1c30c await act(async () => ...) (#14853)
This took a while, but I'm happy I went through it. Some key moments - recursively flushing effects, flushing microtasks on each async turn, and my team's uncompromising philosophy on code reuse. Really happy with this. I still want to expand test coverage, and I have some more small related todos, but this is good to land. On to the next one. 

Soundtrack to landing this - https://open.spotify.com/track/0MF8I8OUo8kytiOo8aSHYq?si=gSWqUheKQbiQDXzptCXHTg

* hacked up act(async () => {...})

* move stuff around

* merge changes

* abstract .act warnings and stuff. all renderers. pass all tests.

* move testutils.act back into testutils

* move into scheduler, rename some bits

* smaller bundle

* a comment for why we don't do typeof === 'function'

* fix test

* pass tests - fire, prod

* lose actContainerElement

* tighter

* write a test for TestRenderer

it's an odd one, because not only does sync act not flush effects correctly, but the async one does (wut). verified it's fine with the dom version.

* lint

* rewrote to move flushing logic closer to the renderer

the scheduler's `flushPassiveEffects` didn't work as expected for the test renderer, so I decided to go back to the hack (rendering a dumb container) This also makes reactdom not as heavy (by a few bytes, but still).

* move it around so the delta isn't too bad

* cleanups

fix promise chaining
propagate errors correctly
test for thenable the 'right' way
more tests!
tidier!
ponies!

* Stray comment

* recursively flush effects

* fixed tests

* lint, move noop.act into react-reconciler

* microtasks when checking if called, s/called/calledLog, cleanup

* pass fb lint

we could have globally changed our eslint config to assume Promise is available, but that means we expect a promise polyfill on the page, and we don't yet. this code is triggered only in jest anyway, and we're fairly certain Promise will be available there. hence, the once-off disable for the check

* shorter timers, fix a test, test for Promise

* use global.Promise for existence check

* flush microtasks

* a version that works in browsers (that support postMessage)

I also added a sanity fixture inside fixtures/dom/ mostly for me.

* hoist flushEffectsAndMicroTasks

* pull out tick logic from ReactFiberScheduler

* fix await act (...sync) hanging

- fix a hang when awaiting sync logic
- a better async/await test for test renderer

* feedback changes

- use node's setImmediate if available
- a warning if MessageChannel isn't available
- rename some functions

* pass lint/flow checks (without requiring a Promise polyfill/exclusion)

* prettier

the prettiest, even.

* use globalPromise for the missed await warning

* __DEV__ check for didWarnAboutMessageChannel

* thenables and callbacks instead of promises, pass flow/lint

* tinier. better.

- pulled most bits out of FiberScheduler
- actedUpdates uses callbacks now

* pass build validation

* augh prettier

* golfing 7 more chars

* Test that effects are not flushed without also flushing microtasks

* export doesHavePendingPassiveEffects, nits

* createAct()

* dead code

* missed in merge?

* lose the preflushing bits

* ugh prettier

* removed `actedUpdates()`, created shared/actingUpdatesScopeDepth

* rearrange imports so builds work, remove the hack versions of flushPassiveEffects

* represent actingUpdatesScopeDepth as a tuple [number]

* use a shared flag on React.__SECRET...

* remove createAct, setup act for all relevant renderers

* review feedback

shared/enqueueTask

import ReactSharedInternals from 'shared/ReactSharedInternals';

simpler act() internals

ReactSharedInternals.ReactShouldWarnActingUpdates

* move act() implementation into createReactNoop

* warnIfNotCurrentlyActingUpdatesInDev condition check order
2019-04-02 22:33:31 +01:00
Dominic Gannaway
6a1e6b2f78 Experimental event API: loosen EventTarget constraints and warnings (#15292)
* Remove warning for event targets being direct children of event component

* Addressed feedback and added more test coverage + warnings
2019-04-02 19:49:28 +01:00
Dominic Gannaway
9444a54720 Warn on nested EventTragets in experimental event API (#15287) 2019-04-01 15:47:03 +01:00
Dominic Gannaway
b83e01cade Adds more scaffolding for experimental event API (#15112)
* Adds more scaffolding for experimental event API
2019-03-20 11:20:17 +00:00
Andrew Clark
6a4a261ee8 Test suspended children are hidden before layout in persistent mode (#15030)
Refs behave differently in persistent mode, so instead of a ref, the
persistent mode version of this test asserts on the output of the
host tree.
2019-03-11 11:19:20 -07:00
Andrew Clark
bc8bd24c14 Run persistent mode tests in CI (#15029)
* Add command to run tests in persistent mode

* Convert Suspense fuzz tester to use noop renderer

So we can run it in persistent mode, too.

* Don't mutate stateNode in appendAllChildren

We can't mutate the stateNode in appendAllChildren because the children
could be current.

This is a bit weird because now the child that we append is different
from the one on the fiber stateNode. I think this makes conceptual
sense, but I suspect this likely breaks an assumption in Fabric.

With this approach, we no longer need to clone to unhide the children,
so I removed those host config methods.

Fixes bug surfaced by fuzz tester. (The test case that failed was the
one that's already hard coded.)

* In persistent mode, disable test that reads a ref

Refs behave differently in persistent mode. I added a TODO to write
a persistent mode version of this test.

* Run persistent mode tests in CI

* test-persistent should skip files without noop

If a file doesn't reference react-noop-renderer, we shouldn't bother
running it in persistent mode, since the results will be identical to
the normal test run.

* Remove module constructor from placeholder tests

We don't need this now that we have the ability to run any test file in
either mutation or persistent mode.

* Revert "test-persistent should skip files without noop"

Seb objected to adding shelljs as a dep and I'm too lazy to worry about
Windows support so whatever I'll just revert this.

* Delete duplicate file
2019-03-11 10:56:34 -07:00
Andrew Clark
3f4852fa5f Run Placeholder tests in persistent mode, too (#15013)
* Convert ReactSuspensePlaceholder tests to use noop

Instead of the test renderer, since test renderer does not support
running in persistent mode.

* Run Placeholder tests in persistent mode, too

* Fix Flow and lint

* Hidden text instances should have correct host context

Adds a test for a subtle edge case that only occurs in persistent mode.

* createHiddenTextInstance -> cloneHiddenTextInstance

This sidesteps the problem where createHiddenTextInstance needs access
to the host context.
2019-03-08 18:53:14 -08:00
Andrew Clark
1e3b6192b5 Import Scheduler directly, not via host config (#14984)
* Import Scheduler directly, not via host config

We currently schedule asynchronous tasks via the host config. (The host
config is a static/build-time dependency injection system that varies
across different renderers — DOM, native, test, and so on.) Instead of
calling platform APIs like `requestIdleCallback` directly, each renderer
implements a method called `scheduleDeferredCallback`.

We've since discovered that when scheduling tasks, it's crucial that
React work is placed in the same queue as other, non-React work on the
main thread. Otherwise, you easily end up in a starvation scenario where
rendering is constantly interrupted by less important tasks. You need a
centralized coordinator that is used both by React and by other
frameworks and application code. This coordinator must also have a
consistent API across all the different host environments, for
convention's sake and so product code is portable — e.g. so the same
component can work in both React Native and React Native Web.

This turned into the Scheduler package. We will have different builds of
Scheduler for each of our target platforms. With this approach, we treat
Scheduler like a built-in platform primitive that exists wherever React
is supported.

Now that we have this consistent interface, the indirection of the host
config no longer makes sense for the purpose of scheduling tasks. In
fact, we explicitly do not want renderers to scheduled task via any
system except the Scheduler package.

So, this PR removes `scheduleDeferredCallback` and its associated
methods from the host config in favor of directly importing Scheduler.

* Missed an extraneous export
2019-03-06 14:41:45 -08:00