zustand/system/vanilla.js

🐻 Bear necessities for state management in React

System.register([], (function (exports) {
  'use strict';
  return {
    execute: (function () {

      exports('default', createStore);

      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;
      }

    })
  };
}));