[Suggestion]: Make useEffectEvent be usable by default in the challenges or add a new note for useRef's alternative

Summary

Make useEffectEvent be usable by default in Separating Events from Effects' challenges, or add a new note for useRef's alternative.

Page

https://react.dev/learn/separating-events-from-effects

Details

I attempted to solve the first challenge in Separating Events from Effects with useEffectEvent. First, following the previous example, I imported that function with this line:

import { experimental_useEffectEvent as useEffectEvent } from 'react';

Then, I used it with these lines:

const updateCount = useEffectEvent(() => {
  setCount(c => c + increment);
});

However, this error was shown up:

Runtime Error

App.js: _react.experimental_useEffectEvent is not a function (8:37)

   5 |   const [count, setCount] = useState(0);
   6 |   const [increment, setIncrement] = useState(1);
   7 | 
>  8 |   const updateCount = useEffectEvent(() => {
                                            ^
   9 |     setCount(c => c + increment);
  10 |   });
  11 | 

Therefore, by default, I can't use useEffectEvent for that exercise. I wrote "by default" because maybe it can be used by opening it in CodeSandbox. It looks like an extra effort for me, so I haven't tried it yet.

One of the solution I found for this challenge is using useRef. I think, the key for this challenge is how to avoid passing reactive elements to the Effect. Because useRef somehow can be treated as local variable which can be changed outside of render, and the interval itself is in-between render, I think it's safe to use. I need to make a Ref consistent with increment state. So, I modified each callback function of the increment buttons.

Here is my solution:

import { useState, useEffect, useRef } from 'react';

export default function Timer() {
  const [count, setCount] = useState(0);
  const [increment, setIncrement] = useState(1);
  const incrementRef = useRef(1);

  function decreaseIncrement() {
    const prevIncrement = increment;
    const newIncrement = prevIncrement - 1;
    setIncrement(newIncrement);
    incrementRef.current = newIncrement;
  }

  function increaseIncrement() {
    const prevIncrement = increment;
    const newIncrement = prevIncrement + 1;
    setIncrement(newIncrement);
    incrementRef.current = newIncrement;
  }

  useEffect(() => {
    const id = setInterval(() => {
      const localIncrement = incrementRef.current;
      setCount(c => c + localIncrement);
    }, 1000);
    return () => {
      clearInterval(id);
    };
  }, []);

  return (
    <>
      <h1>
        Counter: {count}
        <button onClick={() => setCount(0)}>Reset</button>
      </h1>
      <hr />
      <p>
        Every second, increment by:
        <button disabled={increment === 0} onClick={() => {
          decreaseIncrement()
        }}>–</button>
        <b>{increment}</b>
        <button onClick={() => {
          increaseIncrement();
        }}>+</button>
      </p>
    </>
  );
}

It would be better if the useRef's alternative is included as a new note in Separating Events from Effects section.

Inizia dalla pagina Separating Events from Effects e riproduci la prima challenge usando l’import documentato di useEffectEvent. Determina se l’ambiente della challenge debba supportare quell’API oppure se la pagina debba documentare l’alternativa useRef; il lavoro è completo quando l’approccio scelto è disponibile o chiaramente spiegato nella challenge e nelle indicazioni correlate.