import { useContext, createContext, useState, useEffect } from 'react' import localStorage from 'localStorage' const ThemeContext = createContext() export function ThemeProvider ({ children }) { // 初始值 const defaultTheme = localStorage.getItem('theme') const [theme, changeTheme] = useState() useEffect(() => { changeTheme(defaultTheme) }) return ( {children} ) } export const useTheme = () => useContext(ThemeContext)