Controlling cheap USB LED notifiers with nodejs and node-hid

webmail.js

/* Controlling cheap USB LED notifiers with node-hid */

var Notifier = function(hid) {
    this.hid = hid;
    this.colors = ['OFF', 'BLUE', 'RED', 'GREEN', 'CYAN', 'PURPLE', 'YELLOW', 'WHITE'];
};
Notifier.prototype.write = function(arBytes) {
    this.hid.write(arBytes);
};
Notifier.prototype.color = function(value) {
    var color;
    if (typeof value == 'number') {
        color = value;
    }
    if (typeof value == 'string') {
        color = this.colors.indexOf(value);
    }
    this.write([ color, 0, 0, 0, 0, 255, 0, 0 ] );
    return this;
};
Notifier.prototype.off = function() {
    this.color(Notifier.OFF);
    return this;
};
Notifier.prototype.play = function(seq, delay, loop, i) {
    var self = this;
    var color;
    if (typeof loop === 'undefined') {
        loop = false;
    }
    if (typeof i === 'undefined') {
        i = 0;
    }

    color = seq[i];
    if (i < seq.length) {
        this.color(color);
        i++;
    } else {
        if (loop) {
            i = 0;
        } else {
            return;
        }
    }
    setTimeout(function(){
        self.play(seq, delay, loop, i);
    }, delay);
};

/******************************************************************************/

var HID = require('HID');

var vendor = 4756;
var product = 4896;
var hid = new HID.HID(vendor, product);
var notifier = new Notifier(hid);

process.on('SIGINT', function () {
    notifier.color('OFF');
    process.exit();
});

notifier.play(
    ['RED','YELLOW','GREEN','CYAN','PURPLE'],
    500,
    true
);