reactjs / reactjs/react.dev

Problem with recommending startTransition in design system event handlers?

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Description

we generally recommend to bake useTransition into the design system components of your app
https://reactjs.org/docs/concurrent-mode-patterns.html#baking-transitions-into-the-design-system

 // Button component in design system event handler:

  function handleClick() {
    startTransition(() => {
      onClick();
    });
  }

Couldn't this lead to the problem mentioned later?

Try typing into the input now. Something’s wrong! The input is updating very slowly
https://reactjs.org/docs/concurrent-mode-patterns.html#splitting-high-and-low-priority-state

The answer to this problem is to split the state in two parts: a “high priority” part that updates immediately, and a “low priority” part that may wait for a transition.

Solution:

function handleChange(e) {
  const value = e.target.value;
  
  // Outside the transition (urgent)
  setQuery(value);

  startTransition(() => {
    // Inside the transition (may be delayed)
    setResource(fetchTranslation(value));
  });
}

If your design system components wrap all their event handlers in startTransition then how would you make a setState call in your handler run outside of a transition?

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Review the linked Concurrent Mode Patterns sections on baking transitions into design-system components and splitting high- and low-priority state. Use the issue's event-handler examples as the starting point; done means the documentation clearly explains whether design-system handlers should wrap callbacks in startTransition and how urgent updates can remain outside a transition.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react
Domain
documentation
Issue type
Documentation
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
30/100

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