myLib.js

Number.prototype.times = function(cb){
    for (var i = 0; i < this; i++) {
        cb();
    }
}

Number.prototype.to = function(n, step){
    var array = [];
    step = (typeof step != 'undefined') ? step : 1;
    if (n > this){
        for (var i = 0; i < n; i += step) {
            array.push(this + i);
        }
    } else if (n < this) {
        for(var i = 0; i < this; i += step){
            array.push(this - i);
        }
    } else {
        return [n];
    }
    return array;
}

Number.prototype.isOdd = function(){
    return (this % 2 == 1);
}

Number.prototype.isEven = function(){
    return (this % 2 == 0);
}

Array.prototype.sample = function(){
    return this[Math.floor(Math.random() * this.length)];
}

Array.prototype.first = function(n){
    n = (typeof n != 'undefined') ? n : 1;
    return this.slice(0, n);
}

Array.prototype.last = function(n){
    n = (typeof n != 'undefined') ? n - 1 : 0;
    return this.slice(this.length - 1 - n, this.length);
}

var rand = function(min, max){
    if (typeof min == 'undefined' && typeof max == 'undefined') {
        return Math.random();
    }
    return Math.floor(Math.random() * max) + min;
}