Node.js socket.unref() 方法

socket.unref()方法是 dgram 模块中 Socket 类的内置应用程序编程接口，用于允许进程退出，即使套接字仍在侦听。

句法：

const socket.unref()

参数：此方法不接受任何参数。

返回值：此方法返回包含其中所有信息的特定套接字的引用。

示例 1：文件名：index.js

// Node.js program to demonstrate the
// server.unref() property
  
// Importing dgram module
var dgram = require('dgram');
  
// Creating and initializing client
// and server socket
var client = dgram.createSocket("udp4");
var server = dgram.createSocket("udp4");
  
// Handling the message event
server.on("message", function (msg) {
  
    // Displaying the client message
    process.stdout.write("UDP String: " 
                    + msg + "\n");
  
    // Exiting process
    process.exit();
  
})// Binding server with port
    .bind(1234, () => {
  
        // Getting the reference of the server
        // by using unref() method
        const size = server.unref();
  
        // Display the result
        console.log(size.eventNames());
    });
  
// Client sending message to server
client.send("Hello", 0, 7, 1234, "localhost");

输出：

[ 'message' ]
UDP String: Hello

示例 2：文件名：index.js

// Node.js program to demonstrate the
// server.unref() method
  
// Importing dgram module
var dgram = require('dgram');
  
// Creating and initializing client
// and server socket
var client = dgram.createSocket("udp4");
var server = dgram.createSocket("udp4");
  
// Handling the message event
server.on("message", function (msg) {
  
    // Displaying the client message  
    process.stdout.write("UDP String: "
            + msg + "\n");
  
    // Exiting process 
    process.exit();
});
  
// Handling the listening event
server.on('listening', () => {
  
    // Getting address information
    // for the server
    const address = server.address();
  
    // Display the result
    console.log(`server listening 
        ${address.address}:${address.port}`);
});
  
// Binding server with port address
// by using bind() method
server.bind(1234, () => {
  
    // Getting the reference of server
    // by using unref() methods
    const size = server.unref();
  
    // Display the result
    console.log(size.eventNames());
});
  
// Client sending message to server
client.send("Hello", 0, 7, 1234, "localhost");

使用以下命令运行 index.js 文件：

node index.js

输出：

server listening 0.0.0.0:1234
[ 'message', 'listening' ]
UDP String: Hello

参考： https://nodejs.org/dist/latest-v12.x/docs/api/dgram.html#dgram_socket_unref