Base85 ZeroMQ encode 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-:+=^!/*?&<>()[]{}@%$#

Base85ZeroMQ.js

// https://github.com/noseglid/base85
function z85encode(buffer) {
    var enctable = {
        0: '0',
        1: '1',
        2: '2',
        3: '3',
        4: '4',
        5: '5',
        6: '6',
        7: '7',
        8: '8',
        9: '9',
        10: 'a',
        11: 'b',
        12: 'c',
        13: 'd',
        14: 'e',
        15: 'f',
        16: 'g',
        17: 'h',
        18: 'i',
        19: 'j',
        20: 'k',
        21: 'l',
        22: 'm',
        23: 'n',
        24: 'o',
        25: 'p',
        26: 'q',
        27: 'r',
        28: 's',
        29: 't',
        30: 'u',
        31: 'v',
        32: 'w',
        33: 'x',
        34: 'y',
        35: 'z',
        36: 'A',
        37: 'B',
        38: 'C',
        39: 'D',
        40: 'E',
        41: 'F',
        42: 'G',
        43: 'H',
        44: 'I',
        45: 'J',
        46: 'K',
        47: 'L',
        48: 'M',
        49: 'N',
        50: 'O',
        51: 'P',
        52: 'Q',
        53: 'R',
        54: 'S',
        55: 'T',
        56: 'U',
        57: 'V',
        58: 'W',
        59: 'X',
        60: 'Y',
        61: 'Z',
        62: '.',
        63: '-',
        64: ':',
        65: '+',
        66: '=',
        67: '^',
        68: '!',
        69: '/',
        70: '*',
        71: '?',
        72: '&',
        73: '<',
        74: '>',
        75: '(',
        76: ')',
        77: '[',
        78: ']',
        79: '{',
        80: '}',
        81: '@',
        82: '%',
        83: '$',
        84: '#'
    };
    var padding = (buffer.length % 4 === 0) ? 0 : 4 - buffer.length % 4;
    var result = '';
    for (var i = 0; i < buffer.length; i += 4) {

        /* 32 bit number of the current 4 bytes (padded with 0 as necessary) */
        var num = ((buffer[i] << 24) >>> 0) + // Shift right to force unsigned number
            (((i + 1 > buffer.length ? 0 : buffer[i + 1]) << 16) >>> 0) +
            (((i + 2 > buffer.length ? 0 : buffer[i + 2]) << 8) >>> 0) +
            (((i + 3 > buffer.length ? 0 : buffer[i + 3]) << 0) >>> 0);

        /* Create 5 characters from '!' to 'u' alphabet */
        var block = [];
        for (var j = 0; j < 5; ++j) {
            block.unshift(enctable[num % 85]);
            num = Math.floor(num / 85);
        }

        /* And append them to the result */
        result += block.join('');
    }

    return result.substring(0, result.length - padding);
}


// Alternative (sometimes not working as expected, returns null)
// https://github.com/msealand/z85.node
function z85encode(data) {
    if ((data.length % 4) != 0) {
        return null;
    }
    var encoder = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-:+=^!/*?&<>()[]{}@%$#";
    var str = "",
        byte_nbr = 0,
        size = data.length,
        value = 0;
    while (byte_nbr < size) {
        var characterCode;
        if (typeof data == "string") {
            characterCode = data.charCodeAt(byte_nbr++);
        } else {
            characterCode = data[byte_nbr++];
        }
        value = (value * 256) + characterCode;
        if ((byte_nbr % 4) == 0) {
            var divisor = 85 * 85 * 85 * 85;
            while (divisor >= 1) {
                var idx = Math.floor(value / divisor) % 85;
                str += encoder[idx];
                divisor /= 85;
            }
            value = 0
        }
    }
    return str;
}