zustand/esm/vanilla.mjs

🐻 Bear necessities for state management in React

function createStore(createState) {
  let state;
  const listeners = /* @__PURE__ */ new Set();
  const setState = (partial, replace) => {
    const nextState = typeof partial === "function" ? partial(state) : partial;
    if (nextState !== state) {
      const previousState = state;
      state = replace ? nextState : Object.assign({}, state, nextState);
      listeners.forEach((listener) => listener(state, previousState));
    }
  };
  const getState = () => state;
  const subscribeWithSelector = (listener, selector = getState, equalityFn = Object.is) => {
    console.warn("[DEPRECATED] Please use `subscribeWithSelector` middleware");
    let currentSlice = selector(state);
    function listenerToAdd() {
      const nextSlice = selector(state);
      if (!equalityFn(currentSlice, nextSlice)) {
        const previousSlice = currentSlice;
        listener(currentSlice = nextSlice, previousSlice);
      }
    }
    listeners.add(listenerToAdd);
    return () => listeners.delete(listenerToAdd);
  };
  const subscribe = (listener, selector, equalityFn) => {
    if (selector || equalityFn) {
      return subscribeWithSelector(listener, selector, equalityFn);
    }
    listeners.add(listener);
    return () => listeners.delete(listener);
  };
  const destroy = () => listeners.clear();
  const api = { setState, getState, subscribe, destroy };
  state = createState(setState, getState, api);
  return api;
}

export { createStore as default };