samcooke98/will-this-react-global-state-work-in-concurrent-mode

Checking tearing in React concurrent mode

Will this React global state work in concurrent mode?

Checking tearing in React concurrent mode

Introduction

In react-redux, there's a theoretical issue called "tearing" that might occur in React concurrent mode.

Let's try to check it!

What is tearing?

• Stack Overflow
• Talk by Mark Erikson
• Talk by Flarnie Marchan

How does it work?

A small app is implemented with each library. The state has one count. The app shows the count in fifty components.

There's a button outside of React and if it's clicked it will trigger state mutation. This is to emulate mutating an external state outside of React, for example updating state by Redux middleware.

The render has intentionaly expensive computation. If the mutation happens during rendering with in a tree, there could be an inconsistency in the state. If it finds the inconsistency, the test will fail.

How to run

git clone https://github.com/dai-shi/will-this-react-global-state-work-in-concurrent-mode.git
cd will-this-react-global-state-work-in-concurrent-mode
npm install
npm run build-all
PORT=8080 npm run http-server &
PORT=8080 npm run jest

You can also test it by opening http://localhost:8080/react-redux in your browser, and click the button very quickly. (check the console log)

Screencast

Result

Raw Output

  react-redux
    check with events from outside
      ✓ check 1: updated properly (3201ms)
      ✕ check 2: no tearing during update (23ms)
      ✓ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (1387ms)
    check with useTransaction
      ✓ check 5: updated properly with transition (2527ms)
      ✕ check 6: no tearing with transition (2ms)
      ✕ check 7: proper branching with transition (5444ms)
  reactive-react-redux
    check with events from outside
      ✓ check 1: updated properly (3169ms)
      ✓ check 2: no tearing during update (1ms)
      ✓ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (1179ms)
    check with useTransaction
      ✓ check 5: updated properly with transition (2462ms)
      ✓ check 6: no tearing with transition (1ms)
      ✕ check 7: proper branching with transition (7450ms)
  react-tracked
    check with events from outside
      ✓ check 1: updated properly (7851ms)
      ✓ check 2: no tearing during update (1ms)
      ✓ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (2323ms)
    check with useTransaction
      ✓ check 5: updated properly with transition (3531ms)
      ✓ check 6: no tearing with transition (1ms)
      ✓ check 7: proper branching with transition (3584ms)
  constate
    check with events from outside
      ✓ check 1: updated properly (8586ms)
      ✓ check 2: no tearing during update (1ms)
      ✓ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (2325ms)
    check with useTransaction
      ✓ check 5: updated properly with transition (4671ms)
      ✓ check 6: no tearing with transition (1ms)
      ✓ check 7: proper branching with transition (4533ms)
  zustand
    check with events from outside
      ✓ check 1: updated properly (3181ms)
      ✕ check 2: no tearing during update (21ms)
      ✓ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (1413ms)
    check with useTransaction
      ✓ check 5: updated properly with transition (2544ms)
      ✕ check 6: no tearing with transition (2ms)
      ✕ check 7: proper branching with transition (5426ms)
  react-sweet-state
    check with events from outside
      ✓ check 1: updated properly (11104ms)
      ✕ check 2: no tearing during update (1ms)
      ✕ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (2344ms)
    check with useTransaction
      ✕ check 5: updated properly with transition (3968ms)
      ✕ check 6: no tearing with transition (37ms)
      ✕ check 7: proper branching with transition (8684ms)
  storeon
    check with events from outside
      ✓ check 1: updated properly (3152ms)
      ✕ check 2: no tearing during update (21ms)
      ✓ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (1438ms)
    check with useTransaction
      ✕ check 5: updated properly with transition (2658ms)
      ✓ check 6: no tearing with transition (19ms)
      ✕ check 7: proper branching with transition (7419ms)
  react-hooks-global-state
    check with events from outside
      ✓ check 1: updated properly (8612ms)
      ✓ check 2: no tearing during update (1ms)
      ✓ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (1099ms)
    check with useTransaction
      ✓ check 5: updated properly with transition (3500ms)
      ✓ check 6: no tearing with transition (1ms)
      ✕ check 7: proper branching with transition (7335ms)
  use-context-selector
    check with events from outside
      ✓ check 1: updated properly (8620ms)
      ✓ check 2: no tearing during update (2ms)
      ✓ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (2380ms)
    check with useTransaction
      ✓ check 5: updated properly with transition (3532ms)
      ✓ check 6: no tearing with transition (2ms)
      ✓ check 7: proper branching with transition (2693ms)
  mobx-react-lite
    check with events from outside
      ✓ check 1: updated properly (2836ms)
      ✕ check 2: no tearing during update (1ms)
      ✓ check 3: ability to interrupt render (1ms)
      ✓ check 4: proper update after interrupt (1247ms)
    check with useTransaction
      ✓ check 5: updated properly with transition (2629ms)
      ✕ check 6: no tearing with transition (2ms)
      ✕ check 7: proper branching with transition (5583ms)
  use-subscription
    check with events from outside
      ✓ check 1: updated properly (8579ms)
      ✓ check 2: no tearing during update (1ms)
      ✓ check 3: ability to interrupt render
      ✓ check 4: proper update after interrupt (2440ms)
    check with useTransaction
      ✓ check 5: updated properly with transition (4536ms)
      ✓ check 6: no tearing with transition (1ms)
      ✕ check 7: proper branching with transition (7426ms)

	check 1: updated properly	check 2: no tearing during update	check 3: ability to interrupt render	check 4: proper update after interrupt	check 5: updated properly with transition	check 6: no tearing with transition	check 7: proper branching with transition
react-redux	Pass	Fail	Pass	Pass	Pass	Fail	Fail
reactive-react-redux	Pass	Pass	Pass	Pass	Pass	Pass	Fail
react-tracked	Pass	Pass	Pass	Pass	Pass	Pass	Pass
constate	Pass	Pass	Pass	Pass	Pass	Pass	Pass
zustand	Pass	Fail	Pass	Pass	Pass	Fail	Fail
react-sweet-state	Pass	Fail	Fair (just a little bit slow)	Pass	Fail (slow pending)	Fail	Fail
storeon	Pass	Fail	Pass	Pass	Fail (slow pending)	Pass	Fail
react-hooks-global-state	Pass	Pass	Pass	Pass	Pass	Pass	Fail
use-context-selector (w/ useReducer)	Pass	Pass	Pass	Pass	Pass	Pass	Pass
mobx-react-lite	Pass	Fail	Pass	Pass	Pass	Fail	Fail
use-subscription (w/ redux)	Pass	Pass	Pass	Pass	Pass	Pass	Fail

Caution

Do no believe the result too much. The test is done in a very limited way. Something might be wrong.

Caution2

We are not yet sure what the final conurrent mode would be. It's likely that there could be some issues other than "tearing."

If you are interested

The reason why I created this is to promote my projects!

• react-tracked
• reactive-react-redux

The feature of these libraries is not only concurrent mode friendly, but also state usage tracking.