README.md

zustand-signal

Another React binding for Zustand

What it is

Typically, Zustand store is a React hook you can just use in React. There's alternative library called use-zustand.

This library provides yet another method. It follows jotai-signal, which is inspired by @preact/signals-react.

It allows to use the Zustand store in React without using hooks. We don't need to follow the rules of hooks.

How to use it

/** @jsxImportSource zustand-signal */

import createStore from 'zustand/vanilla';
import { $ } from 'zustand-signal';

const store = createStore((set) => ({
  count: 0,
  inc: () => set((state) => ({ count: state.count + 1 })),
}));

setInterval(() => {
  store.getState().inc();
}, 100);

const Counter = () => <div>Count: {$(store).count}</div>;

How it works

The pragma at the first line does the trick. It will transform the code with signal to the code that React can handle.

Original code

/** @jsxImportSource zustand-signal */

const Counter = () => (
  <div>
    Count: {$(store).count} ({Math.random()})
  </div>
);

Pseudo transformed code

import { useEffect, useMemo, useReducer } from 'react';

const Counter = () => {
  const [, rerender] = useReducer((c) => c + 1, 0);
  useEffect(() => {
    let lastValue;
    const unsubscribe = store.subscribe(() => {
      const nextValue = store.getState().count;
      if (lastValue !== nextValue) {
        lastValue = nextValue;
        rerender();
      }
    });
    return unsubscribe;
  }, []);
  return (
    <div>
      {useMemo(() => 'Count: ', [])}
      {store.getState().count}
      {useMemo(() => ` (${Math.random()})`, [])}
    </div>
  );
};