react如何创建一个状态仓库

使用 useState 创建组件内部状态

在 React 中，最简单的状态管理方式是使用 useState Hook。适用于组件内部的局部状态管理。

import React, { useState } from 'react';

function Counter() {
  const [count, setCount] = useState(0); // 初始化状态
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

使用 useReducer 管理复杂状态

当状态逻辑较复杂时，useReducer 更适合。它通过 reducer 函数集中处理状态更新。

import React, { useReducer } from 'react';

const reducer = (state, action) => {
  switch (action.type) {
    case 'increment':
      return { count: state.count + 1 };
    default:
      return state;
  }
};

function Counter() {
  const [state, dispatch] = useReducer(reducer, { count: 0 });
  return (
    <div>
      <p>Count: {state.count}</p>
      <button onClick={() => dispatch({ type: 'increment' })}>Increment</button>
    </div>
  );
}

使用 Context API 实现全局状态

对于跨组件的状态共享，可以通过 createContext 和 useContext 实现轻量级全局状态管理。

import React, { createContext, useContext, useState } from 'react';

const CountContext = createContext();

function CountProvider({ children }) {
  const [count, setCount] = useState(0);
  return (
    <CountContext.Provider value={{ count, setCount }}>
      {children}
    </CountContext.Provider>
  );
}

function Counter() {
  const { count, setCount } = useContext(CountContext);
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

function App() {
  return (
    <CountProvider>
      <Counter />
    </CountProvider>
  );
}

使用第三方库（如 Redux、Zustand）

对于大型应用，推荐使用专业状态管理库：

Redux 示例

import { createStore } from 'redux';
import { Provider, useSelector, useDispatch } from 'react-redux';

const store = createStore((state = { count: 0 }, action) => {
  switch (action.type) {
    case 'INCREMENT':
      return { count: state.count + 1 };
    default:
      return state;
  }
});

function Counter() {
  const count = useSelector(state => state.count);
  const dispatch = useDispatch();
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => dispatch({ type: 'INCREMENT' })}>Increment</button>
    </div>
  );
}

function App() {
  return (
    <Provider store={store}>
      <Counter />
    </Provider>
  );
}

Zustand 示例（轻量级替代方案）

import create from 'zustand';

const useStore = create(set => ({
  count: 0,
  increment: () => set(state => ({ count: state.count + 1 })),
}));

function Counter() {
  const { count, increment } = useStore();
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={increment}>Increment</button>
    </div>
  );
}