There exist a million (or many) global state solutions in React. It seems like the community is struggling to find the best solution. So here I'm going to come with yet another one.

Recently Vue 3 was released. I know, Vue is another framework, but Vue solves the reactivity in a way that it's not tied to the framework. Which means we can use the reactivity everywhere, including React.

First, let's create a store file.
store.js

import { reactive } from 'vue'

const store = reactive({
  count: 0
})

const increase = () => store.count++

export { store, increase }

For an overview of what the Vue composition API can do except for reactive you can get an overview here.

Now we can import the reactive store object and the increase method from the store.js file anywhere we like to. The problem is that React functions don't know when to re-run the function to render the updated values. We will create a custom hook to deal with this.

useStore.js

import { useReducer, useEffect } from 'react'
import { watch } from 'vue'

function useStore(...stores) {
  const [ignored, forceUpdate] = useReducer(x => x + 1, 0)

  useEffect(() => {
    const stopWatch = watch(stores, forceUpdate)
    return stopWatch
  }, [])
}

export default useStore;

We can either use useState or useReducer to make the component update itself. We are watching the params stores with the Vue Composition API and calls forceUpdate on every change. Also, we stop watching on component unmount by returning stopWatch in useEffect. Any amount of stores could be passed into our useStore.

Bump.js

import React from "react";
import { increase } from './store'

export default function Bump() {
  return (
    <button onClick={increase}>+1</button>
  );
}

We could also do store.count++ directly here if we wanted.

Counter.js

import React from "react";
import { store } from './store'
import useStore from './useStore'

export default function Counter() {
  useStore(store)

  return (
    <p>{store.count}</p>
  );
}

Complete example on StackBlitz

Afterthoughts

I actually think this is a nice and simple way of handling a global state. No need for extra components, reduce, dispatch, and/or complete re-assigning of the whole state object. This way we can create exactly as many global stores as we want in a clean way.

Importing the whole Vue might create a bigger bundle size. But you can import only Vue's reactivity module @vue/reactivity and @vue-reactivity/watch or rely on tree shaking for a small bundle.

Now not every developer would want a different way of dealing with component state and global state, so the React way and Vue way might be confusing in the same project. But it's at least an interesting and fun idea.