A test of a React style useState with vue3.

useState.ts

// not working

type SetFunction<T> = (newState: T | ((oldState: T) => T)) => void

export const useState = <T>(initial: T): [T, SetFunction<T>] => {
  const state = ref(initial)

  const setState: SetFunction<T> = (newState) => {
    // @ts-ignore
    state.value = typeof newState === 'function' ? newState(state.value) : newState
  }

  let stateValue = state.value

  watchEffect(() => {
    stateValue = state.value
    console.log('watch', stateValue)
  })

  console.log('useState', stateValue)

  return [stateValue as T, setState]
}