想要显示未运行 mongodb 的失败消息

Question

我想在 mongodb 未运行时在节点 js 中显示“不成功消息”。我的代码仅在 mongod 运行时显示成功或不成功。但是当我关闭 mongo 时，我的网页继续加载提交表单。什么都没有发生/显示。

下面是代码：

const express = require("express");
const path = require("path");
const app = express();
var favicon = require('serve-favicon')
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mongoose.connect('mongodb://localhost/ContactForm', {useNewUrlParser: true});
port = 5500;
var ContactSchema = new mongoose.Schema({
    name: String,
    phone: Number,  
    email: String,
    Company_name: String,
    desc: String,
  });
var Contact = mongoose.model('Contact', ContactSchema);
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app.post("/Contact_Us",(req,res)=>{
    var Myform = new Contact(req.body);
    Myform.save()
    .then(item => {
        res.status(200).render('contact.pug',{ messageq: true});
        res.end();
    })
    .catch(err =>{
        res.status(400).send("Unable to save the message , Please Try after some time");
    });
});

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Answer 1

mongoose.connect('mongodb://localhost/ContactForm', { useNewUrlParser: true }).
catch(error => console.log(error.message));

或者自定义错误信息：

mongoose.connect('mongodb://localhost/ContactForm', { useNewUrlParser: true }).
catch(error => console.log("unable to connect to server));

谢谢