Node.js writeStream.clearScreenDown() 方法

writeStream.clearScreenDown()方法是 tty 模块中 WriteStream 类的内置应用程序编程接口，用于从当前光标向下清除此写入流对象。

句法：

writeStream.clearScreenDown([callback])

参数：此方法不接受任何参数，但会调用回调函数。

返回值：如果写入对象清除，则此方法返回布尔值 true，否则返回 false。

示例 1：文件名：index.js

// Node.js program to demonstrate the
// writeStream.clearScreenDown() 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) {
  
  // Creating and initializing a
  // WriteStream object
  let WriteStream = process.stdout;
  
  // Clearing the write stream object
  // by using clearScreenDown() API
  const col = WriteStream.clearScreenDown();
  
  // Displaying the result
  process.stdout.write(msg + col);
  
  // Exiting process
  process.exit();
})
// Binding server with port
.bind(1234, () => {
});
  
// Client sending message to server
client.send("The line is clear :-  ", 
        0, 26, 1234, "localhost");

输出：

The line is clear :-  true

示例 2：文件名：index.js

// Node.js program to demonstrate the
// writeStream.clearScreenDown() method
  
// Creating and initializing a 
// WriteStream object
let WriteStream = process.stdout;
  
// Clearing the write stream object
// by using clearScreenDown() API
const col = WriteStream.clearScreenDown();
  
// Displaying the result
console.log("The write stream object"
    + " is clear :-  " + col);

使用以下命令运行 index.js 文件：

node index.js

输出：

The write stream object is clear :-  true

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