import useState useEffect from react;export default const SiteRuntime = = const uptime setUptime = useState0; useEffect = const startTime = Datenow; const interval = setInterval

这段代码有一个语法错误。在export default语句中，const应该被移除，因为export语句只能导出函数、类、变量、对象、接口等表达式。正确的代码如下：

import { useState, useEffect } from 'react';

const SiteRuntime = () => { const [uptime, setUptime] = useState(0);

useEffect(() => { const startTime = Date.now(); const interval = setInterval(() => { setUptime(Math.floor((Date.now() - startTime) / 1000)); }, 1000); return () => clearInterval(interval); }, []);

return (

export default SiteRuntime;