node.js - nodemon 应用程序崩溃 - 等待文件更改

Question

我正在自己学习 Node.js，但我不明白为什么会收到该错误“[nodemon] 应用程序崩溃 - 在启动之前等待文件更改..”。我的代码与教程中的代码相同。可能出了什么问题？

感谢您的帮助!

const express = require('express');
const mysql = require('mysql');


//create connection 
const db = mysql.createConnection({
    host: 'localhost',
    user : 'root',
    password : '123456',
});

//connect

db.connect((err)=>{
    if(err){
        throw err;
    }
    console.log("mysql is CONNECTED");
});


const app = express();

app.get('/createdb',(req,res) =>{
    let sql = 'CREATE DATABASE nodemysql';
    db.query(sql,(err, result)=>{
        if(err) throw err;
        console.log(result);
        res.send('database created');
    })
})

app.get('/createdb',()=>{
    console.log("server started on port 3000");
})

app.listen('3000',()=>{
    console.log("server started on port 3000");
});

Answer 1

确保已安装mysql:

npm install mysql --save

尝试console.error(err)，然后return:

var mysql = require("mysql");
var connection = mysql.createConnection({
  host: "example.org",
  user: "bob",
  password: "secret"
});

connection.connect(function(err) {
  if (err) {
    console.error("error connecting: " + err.stack);
    return;
  }

  console.log("connected as id " + connection.threadId);
});