javascript - Nodejs Http Server api 执行流程请解释一下？

Question

我有以下 Nodejs 程序

var http = require('http');
var url = require('url');
var server = http.createServer((req,res)=>{
  console.log("Enter into the 3000 port");
  res.end("hello world")
  console.log("Enter into the 3000 port");
}).listen(3000,()=>{console.log("the server is listen to the port 3000");});

我在浏览器中加载 localhost:3000 时运行这些代码，当我编写 console.log("Enter into the 3000 port"); 来检查内部执行情况时，我得到了以下输出。输出:

the server is listen to the port 3000
Enter into the 3000 port
Enter into the 3000 port
Enter into the 3000 port
Enter into the 3000 port

但是我已经写了代码console.log("进入3000端口");在代码中两次，但我不明白为什么它在单个请求上调用两次，当我再次发送请求时，它再次向我显示一些输出，任何人都可以解释。

Answer 1

var http = require('http');
var url = require('url');
var server = http.createServer((req,res)=>{
  if (req.url === '/favicon.ico') { return } // if you don't serve this hit 
  console.log(req.url);
  console.log("Enter into the 3000 port");
  res.end("hello world")
  console.log("Enter into the 3000 port");
}).listen(3000,()=>{console.log("the server is listen to the port 3000");})

most of the browsers look for *favicon.ico* automatically you can avoid if you want

code