ブーリアン配列とbase64urlを相互変換するやつ

base64.js

;
(function () {
    var Base64 = function () {};
    Base64.prototype = {
        base: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_',
        padding: '=',
        encodeBooleanList: function (b) {
            var t = [], p = 0, i = 0, l = b.length, c;
            while (i < b.length || p > 0) {
                if (p == 0) c = 0;
                c |= ( i < b.length && b[i++]) ? 1 : 0;
                if (++p == 6) {
                    t.push(this.base[c]);
                    p = 0;
                }
                c <<= 1;
            }
            return t.join('');
        },
        decodeBooleanList: function (s) {
            var t = [], l = s.length;
            for (var i = 0; i < l; i++) {
                var c = this.base.indexOf(s.charAt(i));
                for (var p = 5; p >= 0; p--)t.push((c & (1 << p)) > 0);
            }
            return t;
        }
    };
    window.base64 = new Base64();
})();

gistfile1.txt

usage
base64.encodeBooleanList([true, false, ...])

短い
fffttttfttftffttftffffttfttftfttftfttftttfftttfftttfttfttttttttttttffftttfffttfftttttfftftfftftftfffttffftftfffffttftfftttttffttttttftffffftftfftftftt 
=> HtNDa1uc7f_jjPlKjFBp8_QUr

再変換時にパディングがかかる場合がある（末尾にfalse）
ffftttf
-> HA
-> ffftttffffff