refactor: Remove the unnecessary logic

[Flcwl]

🤔 This is a ...

• New feature
• Bug fix
• Site / documentation update
• Demo update
• TypeScript definition update
• Bundle size optimization
• Performance optimization
• Enhancement feature
• Internationalization
• Refactoring
• Code style optimization
• Test Case
• Branch merge
• Other (about what?)

🔗 Related issue link

#1927

💡 Background and solution

const useUnmountedRef = () => {
  const unmountedRef = useRef(false);
  useEffect(() => {
-    unmountedRef.current = false;
    return () => {
      unmountedRef.current = true;
    };
  }, []);
  return unmountedRef;
};

📝 Changelog

Language	Changelog
🇺🇸 English	Remove the unnecessary logic in unmountedRef hook to optimize performance
🇨🇳 Chinese	移除 unmountedRef 中非必要的逻辑，以优化性能

☑️ Self Check before Merge

⚠️ Please check all items below before review. ⚠️

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

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[hchlq]

这个逻辑确实没啥用...

[hchlq]

辛苦帮忙补个单侧...

[Flcwl]

辛苦帮忙补个单侧...

How can I do for it? This change should not need to add additional tests?

[hchlq]

The value of the ref should be false after the component is unmounted and then remounted?

[Flcwl]

The value of the ref should be false after the component is unmounted and then remounted?

@hchlq Hi, My friend~~ I think don't need this case? because the React will reinit react hook state when the component is mounted.
And I also don't see the api like remount in the dependency @testing-library/react-hooks, I don't know how to do it.

[hchlq]

Get it. If not, it's not necessary.

[crazylxr]

LGTM

[miracles1919]

Here is a problem in react 18 StrictMode, effects will run twice in development, see beta website

// react 18 StrictMode

// effect created
unmountedRef => false

// effect destoryed
unmountedRef => true

// effect created
unmountedRef => true

you can see, it's necessary

[Flcwl]

Here is a problem in react 18 StrictMode, effects will run twice in development, see beta website

// react 18 StrictMode

// effect created
unmountedRef => false

// effect destoryed
unmountedRef => true

// effect created
unmountedRef => true

you can see, it's necessary

Oh, So Sorry~
@miracles1919 Thank you very much for your timely feedback, I also found problems in React18 indeed, wrong happened when saving changed files: https://codesandbox.io/s/stoic-cdn-nzjx96?file=/src/App.js