Node/Express：如何分离服务器端和客户端 javascript？

Question

I'm building a JS project to learn new skills, and I'm having trouble delineating between the client-side code and the server-side code. The current setup is a node app with ExpressJS as a dependency.

When I run npm run build && npm run dev , the base html/css is served as expected, but I get an error in my console from the express script.

main.fb6bbcaf.js:116 Uncaught TypeError: Cannot read property 'prototype' of undefined at Object.parcelRequire.node_modules/express/lib/response.js.safe-buffer (response.js:42) at newRequire (main.fb6bbcaf.js:47) at localRequire (main.fb6bbcaf.js:53) at Object.parcelRequire.node_modules/express/lib/express.js.body-parser (express.js:22) at newRequire (main.fb6bbcaf.js:47) at localRequire (main.fb6bbcaf.js:53) at Object.parcelRequire.node_modules/express/index.js../lib/express (index.js:11) at newRequire (main.fb6bbcaf.js:47) at localRequire (main.fb6bbcaf.js:53) at Object.parcelRequire.js/main.js.express (main.js:1)

For reference, I'm still trying to get the example code from the express documentation to run, so my whole main.js file looks like this:

const express = require('express');
const app = express();
const port = 1234;

app.get('/hello', (req, res) => res.send('Hello World!'));

app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`));

I found a person with a similar issue HERE , but what doesn't click for me (and what I can't seem to find a proper question for) is how to separate the client-side and server-side code in my project. I get the feeling that I'm trying to use express in code that's being served to the client, but I don't know where else to put it.

Is there a best-practice location for server-side code in a project that uses both node and express?

Answer 1

Error code say you have problem with Express and body-parser modules. lets fix this from beginning.

// creating new project through cmd line

1)cd to project directory

2)create app.js

3)npm init -y // to create project

4)npm install express body-parser //installing required modules

//open app.js and configure server using below code

const express = require("express");
const bodyParser = require("body-parser");

let app = express();
app.use(bodyParser.urlencoded({extended: true}));

app.get("/",function(req,res){
res.send("Hello world");
})


app.listen(3000, function() {
  console.log("Server started on port 3000");
});

//now run app.js

1)node app.js

2)In browser, head over to "localhost:3000"

This should have solved your problem. body-parser is used when you have post request to server. It shouldn't show any body-parser error if no post request is submitted to your server.