我正在編寫一個react應用程序redux，避免使用react-redux，如果我們手動處理所有調(diào)度的事件，這在技術上是可行的。這是示例代碼。這index.html<!DOCTYPE html><html><head> <script src="https://cdnjs.cloudflare.com/ajax/libs/redux/3.6.0/redux.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.4.1/react.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.4.1/react-dom.js"></script></head><body> <div id="app"></div> <script> const appState= { count: 0, } const reducer = (state, action) => { if (typeof state === 'undefined') state = appState; switch (action.type) { case 'INCREMENT': return {count: state.count+1} case 'DECREMENT': return {count: state.count-1} default: return state } } var store = Redux.createStore(reducer); const App = () => { const [val, setVal] = React.useState(0); handleClick = () => { store.dispatch({type: 'INCREMENT'}) } const unsubscribe = store.subscribe(() => { const state = store.getState(); console.log("Listener is called") setVal(state.count); }); /* unsubscribe() */; return ( <div> <span>{val}</span> <button onClick={handleClick}>Click</button> </div> ); } ReactDOM.render(<App />, document.querySelector("#app")) </script></body></html>在這里，如果我第一次單擊按鈕，它會將日志打印到控制臺一次，但是當我第二次單擊按鈕時，它會在日志上打印兩次語句，這表明來自訂閱的回調(diào)被調(diào)用了兩次，為什么會這樣我該如何防止呢？
為什么我的回調(diào)使用 redux 多次調(diào)用
德瑪西亞99
2023-05-11 14:05:10
