Small node program reading each keystroke from the command line

keyboard-move.js

const readline = require('readline');

const stdin = process.stdin;
readline.emitKeypressEvents(stdin);
stdin.setRawMode(true);

class Coordinates {

    constructor(x = 0, y = 0) {
        this.x = x;
        this.y = y;
    }

    incrementY() {this.y += 1}
    decrementY() {this.y -= 1}
    incrementX() {this.x += 1}
    decrementX() {this.x -= 1}
    toString() {return `[${this.x}, ${this.y}]`}
}

const coordinates = new Coordinates();

stdin.on('keypress', function (_, key) {
  handleKey(key, process);
});

const handleKey = (key, process) => {
    if (key) {
        switch (key.name) {
            case 'up':
                coordinates.incrementY();
                break;
            case 'down':
                coordinates.decrementY();
                break;
            case 'left':
                coordinates.decrementX();
                break;
             case 'right':
                coordinates.incrementX();
                break;   
             case 'c':
                 if (key.ctrl) {
                    process.exit()
                 }   
        }
        console.log(`New coordinates: ${coordinates.toString()}`)
    }
}