Node.js Automatically set current port-CodePudding

require('http').createServer((req,res)=>{res.end();}).listen(80);

listen Is it possible to automatically set this to the current port?

listen(address().port)

do not enter port or wildcard Automatically obtain listen(auto) current port.

CodePudding user response：

The correct way to start a server with http is like this.

const http = require('http');

const server = http.createServer((req, res) => {
    res.end();
})

server.listen(port, hostname, () => {
    console.log(`Server is listening... https://${hostname}:${port}/`)
})

You can take a look at the doc

CodePudding user response：

There is no such thing as "the current port" for a server. A server IP address can be used on a wide range of ports, there is no "current port" for an IP address.

You must specify the port you want your server to run on. That's up to you as a developer to determine. The most common port for an http server is port 80 and for an https server 443, but you can pick other port numbers if you have a particular reason to.

CodePudding user response：

In NodeJS the .listen(<port>, <address>, <callback>) can accept a port number, IP address and a callback function. However, it is possible to call the method with no arguments at all. In this option NodeJS will use a random, unused port number on localhost address.

For example, the following block of code is valid:

const http = require("http");

const server = http.createServer((req, res) => {
  console.log(req);
});

server.listen();

you can inspect the port and IP address of your server by writing:

console.log(server.address());