[Umbrella] Releasing Time Slicing

[gaearon]

Let's use this to track what's missing before Time Slicing is usable internally and in open source.

(Note: the list below is very outdated and doesn't reflect the actual amount of work that went into this)

Initial release (MVP)

Core

• Decide on the recommended low/high pri split pattern
• Fix unstable_deferredUpdates not being respected in interactive event handlers (reproducible in the fixture) Remove buggy unstable_deferredUpdates() #13488
• Fix or provide a workaround for an issue with a chain of synchronous commits on expiration (reproducible in the fixture) Add a failing test for unnecessary commits #13483
• Resuming
• Off-screen <div hidden> API

Scheduler

• Decide on naming (@flarnie, React Core team)
• Adding support for priority (@flarnie)
  • May involve bikeshedding, iteration
  • Will require changes to React Fiber Scheduler
  • Add a fixture showing using JS Scheduler with React and also external JS
• Better handle when tab is backgrounded (@flarnie)
• Improvements to polyfill for rAF
• Integrate and dogfood with internal FB products - see internal task T32773869 (@flarnie)
• Create final API which is not renderer-dependent
• Make react-dom depend on it, and publish it in open source (@flarnie, others internally)

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Related: Suspense Umbrella (#13206)

[flarnie]

Thanks for creating this!
I would change

Figure out if it needs a priority API
to
Implement and try out the priority API

I can pick up that work again next week.

[gaearon]

@flarnie Feel free to edit :-)

[raibima]

hi @gaearon, questions:

1. Is time-slicing a React or ReactDOM specific feature?
2. Any reason why it's currently part of ReactDOM API as opposed to just another React.Component method (e.g., Component.prototype.deferSetState)?

[gaearon]

The unstable_deferredUpdates API is just a placeholder and will be removed. I imagine the actual API we’ll end up with should be renderer-independent.

[TrySound]

Will offscreen api work with fragments? Like this

<React.Fragment hidden={!visible}>
  {content}
</React.Fragment>

[NE-SmallTown]

@TrySound IIRC, React doesn't support any attribute on Fragment except one or two special(I don't remember)?

[TrySound]

@NE-SmallTown I know that Fragment supports only key prop. That's why I'm asking. This will be a quite useful feature for example in windowing.

[ccarse]

I think this needs updated since the latest release? At least it seems so from https://reactjs.org/blog/2018/10/23/react-v-16-6.html#scheduler-experimental ?