@plasius/react-state/dist/index.js

Tiny, testable, typesafe React Scoped Store helper.

// src/types.ts
var __noop = null;

// src/create-scoped-store.tsx
import { createContext, useContext, useRef, useSyncExternalStore } from "react";

// src/store.ts
function createStore(reducer, initialState) {
  let state = initialState;
  const listeners = /* @__PURE__ */ new Set();
  const keyListeners = /* @__PURE__ */ new Map();
  const selectorListeners = /* @__PURE__ */ new Set();
  const getState = () => state;
  const dispatch = (action) => {
    const prevState = state;
    const nextState = reducer(state, action);
    if (Object.is(prevState, nextState)) {
      state = nextState;
      return;
    }
    state = nextState;
    for (const listener of [...listeners]) listener();
    for (const [key, set] of keyListeners.entries()) {
      if (!Object.is(prevState[key], state[key])) {
        for (const listener of [...set]) listener(state[key]);
      }
    }
    selectorListeners.forEach((entry) => {
      const nextValue = entry.selector(state);
      if (!Object.is(entry.lastValue, nextValue)) {
        entry.lastValue = nextValue;
        entry.listener(nextValue);
      }
    });
  };
  const subscribe = (listener) => {
    listeners.add(listener);
    return () => {
      listeners.delete(listener);
    };
  };
  const subscribeToKey = (key, listener) => {
    const set = keyListeners.get(key) ?? /* @__PURE__ */ new Set();
    set.add(listener);
    keyListeners.set(key, set);
    return () => {
      set.delete(listener);
      if (set.size === 0) keyListeners.delete(key);
    };
  };
  const subscribeWithSelector = (selector, listener) => {
    const entry = {
      selector,
      listener,
      lastValue: selector(state)
    };
    selectorListeners.add(entry);
    return () => {
      selectorListeners.delete(entry);
    };
  };
  return {
    getState,
    dispatch,
    subscribe,
    subscribeToKey,
    subscribeWithSelector
  };
}

// src/create-scoped-store.tsx
import { jsx } from "react/jsx-runtime";
function shallowEqual(a, b) {
  if (Object.is(a, b)) return true;
  if (typeof a !== "object" || a === null || typeof b !== "object" || b === null)
    return false;
  const ak = Object.keys(a), bk = Object.keys(b);
  if (ak.length !== bk.length) return false;
  for (let i = 0; i < ak.length; i++) {
    const k = ak[i];
    if (!Object.prototype.hasOwnProperty.call(b, k) || !Object.is(a[k], b[k]))
      return false;
  }
  return true;
}
function createScopedStoreContext(reducer, initialState) {
  const Context = createContext(null);
  const store = createStore(reducer, initialState);
  const Provider = ({ children }) => /* @__PURE__ */ jsx(Context.Provider, { value: store, children });
  const useStore2 = () => {
    const ctx = useContext(Context);
    if (!ctx) throw new Error("Store not found in context");
    return useSyncExternalStore(ctx.subscribe, ctx.getState, ctx.getState);
  };
  const useDispatch2 = () => {
    const ctx = useContext(Context);
    if (!ctx) throw new Error("Dispatch not found in context");
    return (action) => ctx.dispatch(action);
  };
  function useSelector(selector, isEqual = shallowEqual) {
    const ctx = useContext(Context);
    if (!ctx) throw new Error("Store not found in context");
    const state = useSyncExternalStore(
      ctx.subscribe,
      ctx.getState,
      ctx.getState
    );
    const lastRef = useRef(null);
    const last = lastRef.current;
    const nextSelected = selector(state);
    if (last && last.state === state && isEqual(last.selected, nextSelected)) {
      return last.selected;
    }
    lastRef.current = { state, selected: nextSelected };
    return nextSelected;
  }
  return {
    store,
    Context,
    Provider,
    useStore: useStore2,
    useDispatch: useDispatch2,
    useSelector
  };
}

// src/provider.tsx
import { createContext as createContext2, useContext as useContext2, useEffect, useState } from "react";
import { jsx as jsx2 } from "react/jsx-runtime";
var StoreContext = createContext2(void 0);
function useStoreInstance() {
  const store = useContext2(StoreContext);
  if (!store) {
    throw new Error(
      "StoreProvider is missing in the React tree. Wrap your app with <StoreProvider store={...}>."
    );
  }
  return store;
}
function StoreProvider({
  store,
  children
}) {
  return /* @__PURE__ */ jsx2(StoreContext.Provider, { value: store, children });
}
function useStore() {
  const store = useStoreInstance();
  const [state, setState] = useState(() => store.getState());
  useEffect(() => {
    const unsubscribe = store.subscribe(() => {
      setState(store.getState());
    });
    return unsubscribe;
  }, [store]);
  return state;
}
function useDispatch() {
  const store = useStoreInstance();
  return store.dispatch;
}

// src/metadata-store.ts
var MetadataStore = class {
  symbol;
  constructor(description) {
    this.symbol = Symbol(description);
  }
  set(target, meta) {
    Object.defineProperty(target, this.symbol, {
      value: meta,
      writable: false,
      enumerable: false
    });
  }
  get(target) {
    return target[this.symbol];
  }
  has(target) {
    return this.symbol in target;
  }
};
export {
  MetadataStore,
  StoreProvider,
  __noop,
  createScopedStoreContext,
  createStore,
  useDispatch,
  useStore
};
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