React: [Umbrella] Releasing Time Slicing

[gaearon]

Let's use this to track what's missing before Time Slicing is usable internally and in open source.
This list is probably very incomplete, feel free to add more.

Initial release (MVP)

Core

• [x] Decide on the recommended low/high pri split pattern
• [x] Fix unstable_deferredUpdates not being respected in interactive event handlers (reproducible in the fixture) https://github.com/facebook/react/pull/13488
• [x] Fix or provide a workaround for an issue with a chain of synchronous commits on expiration (reproducible in the fixture) https://github.com/facebook/react/pull/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)

---

Related: Suspense Umbrella (https://github.com/facebook/react/issues/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 ?