Res.Sendfile不是错误页面的函数NODE.JS

Question

我正在使用节点表示。我正在尝试创建500错误页面。我做了一个页面和一条测试路线。当我输入错误路由时，它表明app.sendfile不是函数。

let express = require('express');

let app = express();

let path = require('path')

let personRoute = require('./route/person')

app.use((req, res, next)=> {
    console.log(`${new Date().toString()} => ${req.originalUrl}`)
    next()
} )

app.use(personRoute)

app.use(express.static('public'))

app.use((req, res, next) =>
{
    res.status(400).send("Sorry I think that you are lost");
})

app.use((err, res, req, next) =>
{
    console.error(err.stack);
    res.sendFile(path.join(__dirname, '../public/500.html'))

})




const PORT = process.env.PORT || 3000
app.listen(PORT, () => console.info(`Server started on ${PORT}`))