同一主机和端口两次侦听不会触发错误

Question

const http  = require("http");

function createServer(
  name,
  hostname
)
{
  const server = http.createServer(
    (
      request,
      response
    ) =>
    {
      console.log("request on", name);
      response.end(name);
    }
  );

  server.on(
    "error",
    (error) => console.log(`${name} error`, error)
  );

  server.on(
    "close",
    () => console.log(`${name} closed`)
  );

  server.listen(4321, hostname, () => console.log(`${name} listening (${server.listening}) on address`, server.address()));
}

createServer(
  "Server 1",
  "localhost"
);

createServer(
  "Server 2",
  "127.0.0.1"
);

createServer(
  "Server 3",
  "127.0.1.1"
);

createServer(
  "Server 4",
  "localhost"
);

createServer(
  "Server 5",
  "10.9.129.49"
);

createServer(
  "Server 6",
  "localhost"
);

使用Node v6.15.1,v8.14.1和v10.15.0,上面的代码在我的计算机上打印出来:

Server 2 listening (true) on address { address: '127.0.0.1', family: 'IPv4', port: 4321 }
Server 3 listening (true) on address { address: '127.0.1.1', family: 'IPv4', port: 4321 }
Server 5 listening (true) on address { address: '10.9.129.49', family: 'IPv4', port: 4321 }
Server 1 listening (true) on address { address: '127.0.0.1', family: 'IPv4', port: 4321 }
Server 4 listening (true) on address { address: '127.0.0.1', family: 'IPv4', port: 4321 }
Server 6 listening (true) on address { address: '127.0.0.1', family: 'IPv4', port: 4321 }

这怎么可能？我原本预计EADDRINUSE会触发错误.

编辑此问题的先前版本仅显示使用主机名的两台服务器localhost.代码已更新,以证明无论服务器数量或主机如何,问题似乎都会持续存在.

UPDATE

我尝试混合指向我的计算机的不同主机名(localhost,127.0.0.1我的本地IP等),即使address打印的对象显示不同的值,也address()不会发生错误.

我很好奇它是否与Node.js的server.listen方法有关,允许自己被多次调用.也许Node.js检测到我使用的所有主机名绑定到同一个设备和端口,所以它只是"重新打开",就像文档所说的那样.