reactjs / reactjs/react.dev

[Hooks] - callbacks in useState hook examples

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Description

I would like to discuss about using callbacks to create new state which bases on current state in documentation for useState hook.
Current examples can be confusing for new developers which are not very familiar with js.
It would be easier for new developers to learn the rule like newer use value from this.state (for setState) or take current state value from scope (for hooks) to create new state. This simple rule leads to smaller amount of bugs.

So new developers can take this example from https://reactjs.org/docs/hooks-intro.html

import { useState } from 'react';

function Example() {
  // Declare a new state variable, which we'll call "count"
  const [count, setCount] = useState(0);

  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>
        Click me
      </button>
    </div>
  );
}

and convert to something like this:

import { useState } from 'react';

function Example() {
  // Declare a new state variable, which we'll call "count"
  const [count, setCount] = useState(0);

  const handleClick = () => {
    setCount(count + 1);
    setCount(count + 1);
  }

  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={handleClick}>
        Click me
      </button>
    </div>
  );
}

with assumption that it will increment by 2 but it does not (it's based on observation with junior developers).

Shouldn't we change first example (and all 'counter' based examples in docs) to something like this?

import { useState } from 'react';

function Example() {
  // Declare a new state variable, which we'll call "count"
  const [count, setCount] = useState(0);

  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(currentValue => currentValue + 1)}>
        Click me
      </button>
    </div>
  );
}

and create new example to show 'standard' way to set state (example where new state is not based on current one).
Or maybe we should just say it's how JS (closures) works and left examples as is?
What's your opinion? I can create PR with changes but I'm not sure which path to choose. On the one hand it's how JS works but on the other hand I see it's confusing.

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Piste de recherche

Commencez par l’exemple de useState à l’adresse https://reactjs.org/docs/hooks-intro.html et examinez les autres exemples basés sur des compteurs dans la documentation. Cet issue nécessite qu’un maintainer décide s’il faut modifier les exemples ou expliquer le comportement existant ; il sera considéré comme terminé lorsque les indications choisies seront documentées de manière cohérente.

Rédigé par le modèle d'indexation à partir du texte de l'issue.

Évaluation

Stack technique
javascript, react
Domaine
documentation
Type d'issue
Documentation
Difficulté
5/5
Temps estimé
Plus d'une semaine
Activité
À l'abandon
Clarté
À clarifier
Accessibilité débutants
32/100

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