[Hooks] What is accepted on useEffect's 2nd argument

I assume currently it only do equal (===) comparison, since passing array of array isn't preventing it.

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

export default () => {
  let [count, setCount] = useState(0);
  let guard = [0, 1, 2];
  useEffect(() => {
    setTimeout(() => {
      setCount(count + 1);
    }, 2000); // delay to prevent lagging
  }, [guard]);
  return <div>{count}</div>;
};

I don't find anything in current documentation. I think it is needed to add accepted types passed into that 2nd argument.

On side note, I wonder what In the future, the second argument might get added automatically by a build-time transformation. phrase means.

Commencez par le point d’entrée de la documentation de useEffect et par l’exemple de nested-array de l’issue ; vérifiez ce que le deuxième argument accepte et comment la comparaison des dépendances est décrite. Expliquez également la phrase citée concernant build-time-transformation. Le travail est terminé lorsque la documentation répond clairement aux deux questions, y compris au comportement de l’exemple.