该中间件放到最后，通过接受err参数判断是否触发该中间件

/*统一的错误处理日志中间件*/
app.use((err,req, res, next) => {const err_log = `+---------------+-------------------------+错误名称：${err.name},\n错误信息：${err.message},\n错误时间：${new Date()},\n错误堆栈：${err.stack},\n+---------------+-------------------------+`fs.appendFile(path.join(__dirname,"error.log"),err_log,()=>{res.writeHead(500,{'Content-Type':'text/html;charset=utf-8'});res.end(`500 服务器内部错误`);});
})

举例

const express = require('express')
const fs = require('fs')
const path = require('path')
const app = express()app.get('/a',(req, res, next) => {res.end('hello')
})app.get('/',(req, res, next) => {try {const data = JSON.parse("{name:}");res.json(data);}catch (e){next(e);}
})app.get('/',(req, res, next) => {fs.readFile(path.join(__dirname,"ccc.log"),(err,data)=>{if(err){next(err);}});
})/*统一的错误处理日志中间件*/
app.use((err,req, res, next) => {const err_log = `+---------------+-------------------------+错误名称：${err.name},\n错误信息：${err.message},\n错误时间：${new Date()},\n错误堆栈：${err.stack},\n+---------------+-------------------------+`fs.appendFile(path.join(__dirname,"error.log"),err_log,()=>{res.writeHead(500,{'Content-Type':'text/html;charset=utf-8'});res.end(`500 服务器内部错误`);});
})app.listen(3000,()=>{console.log('running```')
})