export default function applyMiddleware(...middlewares) {  return (createStore) => (reducer, preloadedState, enhancer) => {    const store = createStore(reducer, preloadedState, enhancer)    let dispatch = store.dispatch    let chain = []    const middlewareAPI = {      getState: store.getState,      dispatch: (action) => dispatch(action)    }    chain = middlewares.map(middleware => middleware(middlewareAPI))    dispatch = compose(...chain)(store.dispatch)    return {      ...store,      dispatch    }  }}這里參數(shù)為什么要用展開符？ 使用的時(shí)候傳入的是數(shù)組，如：const middlewares = [ thunk, logger ]applyMiddleware(...middlewares)那這樣函數(shù)中 middlewares.map 的 middlewares豈不是 [[thunk, logger]]了么。PS: 奧。。明白了，同時(shí)支持applyMiddleware(thunk, logger)和applyMiddleware(...[thunk, logger])兩種方式調(diào)用。 大家忽略吧