node . js write stream . clearscreendown()方法
原文:https://www . geesforgeks . org/node-js-write stream-clearscreendown-method/
writeStream . clearscreendown()方法是 tty 模块中类 write stream 的内置应用编程接口，用于从当前光标向下清除该写流对象。
语法:
writeStream.clearScreenDown([callback])
参数:这个方法不接受任何参数，但是它调用一个回调函数。
返回值:如果写对象为空，则该方法返回布尔值 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:
// 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
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