BFE.dev solution for React Coding Question
7. useToggle()

This is a fairly simple question. We just need to wrap useState().

import {useState} from 'react'export function useToggle(on: boolean): [boolean, () => void] {  const [state, setState] = useState(on)  const toggle = () => {    setState(state => !state)  }  return [state, toggle]}

Usually we want to stablize the callbacks.

import {useState, useCallback} from 'react'export function useToggle(on: boolean): [boolean, () => void] {  const [state, setState] = useState(on)  const toggle = useCallback(() => {    setState(state => !state)  }, [])  return [state, toggle]}