Very simple bitset operations in JavaScript

bitset.js

/* bitset.js
 * 
 * bitset = new Bitset(64);
 * bitset.toString(); // "0000000000000000000000000000000000000000000000000000000000000000"
 * bitset.setBit(48, 1).setBit(23, 1).setBit(52, 1);
 * bitset.toString(); // "0000000000010001000000000000000000000000100000000000000000000000"
 * bitset.toInt(); // 4785074612469760
 *
 * bitset.fromInt(679642164705874);
 * bitset.toString(); // "0000000000000010011010100010000110000101110011010011101001010010"
 * bitset.getBit(10); // false
 * bitset.getBit(1); // true
 */
var Bitset = (function() {
    function Bitset(size) {
        this.size = size || 32;
        this.bitset = new Array(size);
        this.clear();
    };
    Bitset.prototype.fill = function(value) {
        var i;
        for (i = 0; i < this.size; i++) {
            this.bitset[i] = !!value;
        }
        return this;
    };
    Bitset.prototype.clear = function() {
        this.fill(0);
        return this;
    };
    Bitset.prototype.setBit = function(index, value) {
        if (index < 0 || index >= this.size) {
            return undefined;
        }
        this.bitset[this.size-index-1] = !!value;
        return this;
    };
    Bitset.prototype.getBit = function(index) {
        if (index < 0 || index >= this.size) {
            return undefined;
        }
        return !!this.bitset[this.size-index-1];
    };
    Bitset.prototype.toString = function() {
        var result = "", i;
        for (i = 0; i < this.size; i++) {
            result += (!!this.bitset[i] ? "1" : "0");
        }
        return result;
    };
    Bitset.prototype.toInt = function() {
        var result = 0, base = 1, i;
        for (i = this.size-1; i >= 0; i--) {
            result += base * (!!this.bitset[i])
            base *= 2;
        }
        return result;
    };
    Bitset.prototype.fromInt = function(from) {
        var i, base;
        this.clear();
        for (i = 0; i < this.size; i++) {
            base = Math.pow(2, this.size-i-1);
            this.bitset[i] = !!Math.floor(from / base);
            from = from % base;
        }
        return this;
    };
    return Bitset;
})();