Node.js TTY

Introduction

Node.js TTY is a module that provides a way to interact with the terminal (console) of the operating system. It provides a standard input/output stream and allows developers to create and manipulate terminal outputs and inputs.

Features

Some of the key features of Node.js TTY are:

• Standard input/output streams
• Support for ANSI escape codes
• Ability to create custom input/output streams
• Ability to detect terminal capabilities
• Stream events for handling input/output

Installation

Node.js TTY is included with the core Node.js distribution, so no additional installation is required.

Usage

Standard streams

Node.js TTY provides three standard streams:

• process.stdin: a readable stream for reading data from the console input
• process.stdout: a writable stream for writing data to the console output
• process.stderr: a writable stream for writing data to the console error output

Here's an example of using the process.stdin and process.stdout streams to create a simple echo program:

process.stdin.on('data', (data) => {
  process.stdout.write(`You wrote: ${data.toString()}`);
});

Custom streams

Node.js TTY also allows developers to create custom input/output streams using the Readable and Writable classes.

Here's an example of creating a custom writable stream that converts all input to uppercase:

const { Writable } = require('stream');

class UpperCaseStream extends Writable {
  _write(chunk, encoding, callback) {
    this.emit('data', chunk.toString().toUpperCase());
    callback();
  }
}

process.stdin.pipe(new UpperCaseStream()).pipe(process.stdout);

ANSI escape codes

Node.js TTY supports ANSI escape codes, which can be used to control the appearance of the console output. Here's an example of using ANSI escape codes to change the text color:

process.stdout.write('\x1b[31mHello, world!\x1b[0m');

This will output "Hello, world!" in red.

Terminal capabilities

Node.js TTY provides a isatty() method that can be used to detect whether a particular stream is connected to a terminal or not. Here's an example:

console.log(process.stdout.isTTY ? 'connected to terminal' : 'not connected');

Stream events

Node.js TTY streams emit events for handling input and output. Here's an example of using the data event to read input from the console:

process.stdin.on('data', (data) => {
  console.log(`You wrote: ${data.toString()}`);
});

Conclusion

Node.js TTY is a powerful module that provides developers with a way to interact with the terminal. Whether you're creating a command-line tool or simply need to output data to the console, Node.js TTY has you covered.