Flarnie Marchan 61777a78f6 [scheduler] 3/n Use a linked list instead of map and queue for callback storage (#12893) ...

* [schedule] Use linked list instead of queue and map for storing cbs

NOTE: This PR depends on https://github.com/facebook/react/pull/12880
and https://github.com/facebook/react/pull/12884
Please review those first, and after they land Flarnie will rebase on
top of them.

---

**what is the change?:**
See title

**why make this change?:**
This seems to make the code simpler, and potentially saves space of
having an array and object around holding references to the callbacks.

**test plan:**
Run existing tests

* minor style improvements

* refactor conditionals in cancelScheduledWork for increased clarity

* Remove 'canUseDOM' condition and fix some flow issues w/callbackID type

**what is the change?:**
- Removed conditional which fell back to 'setTimeout' when the
environment doesn't have DOM. This appears to be an old polyfill used
for test environments and we don't use it any more.
- Fixed type definitions around the callbackID to be more accurate in
the scheduler itself, and more loose in the React code.

**why make this change?:**
To get Flow passing, simplify the scheduler code, make things accurate.

**test plan:**
Run tests and flow.

* Rewrite 'cancelScheduledWork' so that Flow accepts it

**what is the change?:**
Adding verification that 'previousCallbackConfig' and
'nextCallbackConfig' are not null before accessing properties on them.

Slightly concerned because this implementation relies on these
properties being untouched and correct on the config which is passed to
'cancelScheduledWork' but I guess we already rely heavily on that for
this whole approach. :\

**why make this change?:**
To get Flow passing.

Not sure why it passed earlier and in CI, but now it's not.

**test plan:**
`yarn flow dom` and other flow tests, lint, tests, etc.

* ran prettier

* Put back the fallback implementation of scheduler for node environment

**what is the change?:**
We had tried removing the fallback implementation of `scheduler` but
tests reminded us that this is important for supporting isomorphic uses
of React.

Long term we will move this out of the `schedule` module but for now
let's keep things simple.

**why make this change?:**
Keep things working!

**test plan:**
Ran tests and flow

* Shorten properties stored in objects by sheduler

**what is the change?:**
`previousScheduledCallback` -> `prev`
`nextScheduledCallback` -> `next`

**why make this change?:**
We want this package to be smaller, and less letters means less code
means smaller!

**test plan:**
ran existing tests

* further remove extra lines in scheduler

2018-05-26 15:55:57 -07:00

..

__tests__

TestRenderer warns if flushThrough is passed the wrong params (#12909)

2018-05-25 14:53:24 -07:00

ReactShallowRenderer.js

Shallow renderer: pass component instance to setState updater as this (#12784)

2018-05-11 18:03:08 +01:00

ReactTestHostConfig.js

Resolve host configs at build time (#12792)

2018-05-19 11:29:11 +01:00

ReactTestRenderer.js

Update Flow to 0.70 (#12875)

2018-05-21 17:54:48 +01:00

ReactTestRendererScheduling.js

[scheduler] 3/n Use a linked list instead of map and queue for callback storage (#12893)

2018-05-26 15:55:57 -07:00