Node.js writeStream.isTTY Property

The writeStream.isTTY property is an inbuilt application programming interface of class WriteStream within ‘tty’ module which is used to check if the write Stream object is an instance of tty or not. It will always return true for tty, writeStream.

Syntax:

const writeStream.isTTY

Return Value: This property returns true if the write Stream object is an instance of tty.

Example 1: Filename: index.js

Javascript

// Node.js program to demonstrate the
// writeStream.isTTY property

// Importing dgram module
const dgram = require('dgram');


// Creating and initializing client
// and server socket
let client = dgram.createSocket("udp4");
let server = dgram.createSocket("udp4");

// Catching the message event
server.on("message", function (msg) {

    // Creating and initializing a
    // WriteStream object
    let WriteStream = process.stdout;

    // Checking if it is instance of TTY
    // or not by using isTTY() method
    const status = WriteStream.isTTY;

    // Displaying the result
    if (status)
        process.stdout.write(msg
            + "an instant of TTY" + "\n");
    else
        process.stdout.write(msg
            + "not an instant of TTY" + "\n");

    // Exiting process
    process.exit();
})

    // Binding server with port
    .bind(1234, () => {
    });

// Client sending message to server
client.send("It is ", 0, 7, 1234, "localhost");

Output:

It is an instant of TTY

Example 2: Filename: index.js

Javascript

// Node.js program to demonstrate the
// writeStream.isTTY() property

// Creating and initializing a
// WriteStream object
let WriteStream = process.stdout;

// Checking if it is instance of
// TTY or not by using isTTY() method
const status = WriteStream.isTTY;

// Displaying the result
if (status)
    console.log("It is an instant of TTY");
else
    console.log("It is not an instant of TTY");

Output:

It is an instant of TTY

Run the index.js file using the following command:

node index.js

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