Run results for: Base64 vs. base64

Run details:
User agent: Mozilla/5.0 (Windows NT 5.1; rv:52.0) Gecko/20100101 Firefox/52.0
Browser: Firefox 52
Operating system: Windows XP
Device Platform: Desktop
Date tested: 4 months ago
Test name	Executions per second
Base64 1	33069.8 Ops/sec
base64 2	13713.0 Ops/sec
Script Preparation code:
const charset = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
const paddingChar = '=';
function encode(input) {
    const paddings = 3 - (input.length % 3 || 3);
    let encoded = '';
    let binaries = '';
    for (let i = 0; i < input.length + paddings; i++) {
        const char = input[i];
        const binary = char ? char.charCodeAt(0).toString(2).padStart(8, '0') : '00000000';
        // the binaries length could only be 0, 2 or 4 because the bits will be consumed once become 6
        switch (binaries.length) {
            case 0:
                encoded += charset[parseInt(binary.slice(0, 6), 2)];
                binaries = binary.slice(6);
                break;
            case 2:
                encoded += charset[parseInt(`${binaries}${binary.slice(0, 4)}`, 2)];
                binaries = binary.slice(4);
                break;
            case 4:
                // the paddings count could only be 0, 1 or 2
                switch (paddings) {
                    case 0:
                        encoded += charset[parseInt(`${binaries}${binary.slice(0, 2)}`, 2)];
                        encoded += charset[parseInt(binary.slice(2), 2)];
                        break;
                    case 1:
                        // when there's only one padding and current char is undedefined (exceeded input string ranged)
                        // which means the last char is a padding char
                        if (!char) {
                            encoded += charset[parseInt(`${binaries}${binary.slice(0, 2)}`, 2)];
                            encoded += paddingChar;
                        }
                        else {
                            encoded += charset[parseInt(`${binaries}${binary.slice(0, 2)}`, 2)];
                            encoded += charset[parseInt(binary.slice(2), 2)];
                        }
                        break;
                    case 2:
                        // when there are 2 paddings and previous char is undedefined (exceeded input string ranged)
                        // which means the last 2 chars are padding chars
                        if (!input[i - 1]) {
                            encoded += paddingChar;
                            encoded += paddingChar;
                        }
                        else {
                            encoded += charset[parseInt(`${binaries}${binary.slice(0, 2)}`, 2)];
                            encoded += charset[parseInt(binary.slice(2), 2)];
                        }
                        break;
                }
                binaries = '';
                break;
        }
    }
    return encoded;
}
function decode(input) {
    let decoded = '';
    let binaries = '';
    for (let i = 0; i < input.length; i++) {
        const char = input[i];
        // once reached the padding char, don't need to continue the loop
        if (char === paddingChar) {
            break;
        }
        const code = charset.indexOf(char);
        const binary = code.toString(2).padStart(6, '0');
        // binaries length could only be 0, 2, 4 or 6 because the bits will be consumed once become 8
        switch (binaries.length) {
            case 0:
                binaries += binary;
                break;
            case 2:
                decoded += String.fromCharCode(parseInt(`${binaries}${binary}`, 2));
                binaries = '';
                break;
            case 4:
                decoded += String.fromCharCode(parseInt(`${binaries}${binary.slice(0, 4)}`, 2));
                binaries = binary.slice(4);
                break;
            case 6:
                decoded += String.fromCharCode(parseInt(`${binaries}${binary.slice(0, 2)}`, 2));
                binaries = binary.slice(2);
                break;
        }
    }
    return decoded;
}

var base64 = {
    encode,
    decode,
};

/**
*
*  Base64 encode / decode
*  http://www.webtoolkit.info/
*
**/
var Base64 = {

    // private property
    _keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",

    // public method for encoding
    encode : function (input) {
        var output = "";
        var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
        var i = 0;

        input = Base64._utf8_encode(input);

        while (i < input.length) {

            chr1 = input.charCodeAt(i++);
            chr2 = input.charCodeAt(i++);
            chr3 = input.charCodeAt(i++);

            enc1 = chr1 >> 2;
            enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
            enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
            enc4 = chr3 & 63;

            if (isNaN(chr2)) {
                enc3 = enc4 = 64;
            } else if (isNaN(chr3)) {
                enc4 = 64;
            }

            output = output +
            this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
            this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
        }
        return output;
    },

    // public method for decoding
    decode : function (input) {
        var output = "";
        var chr1, chr2, chr3;
        var enc1, enc2, enc3, enc4;
        var i = 0;

        input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

        while (i < input.length) {

            enc1 = this._keyStr.indexOf(input.charAt(i++));
            enc2 = this._keyStr.indexOf(input.charAt(i++));
            enc3 = this._keyStr.indexOf(input.charAt(i++));
            enc4 = this._keyStr.indexOf(input.charAt(i++));

            chr1 = (enc1 << 2) | (enc2 >> 4);
            chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
            chr3 = ((enc3 & 3) << 6) | enc4;

            output = output + String.fromCharCode(chr1);

            if (enc3 != 64) {
                output = output + String.fromCharCode(chr2);
            }
            if (enc4 != 64) {
                output = output + String.fromCharCode(chr3);
            }
        }

        output = Base64._utf8_decode(output);

        return output;
    },

    // private method for UTF-8 encoding
    _utf8_encode : function (string) {
        string = string.replace(/\r\n/g,"\n");
        var utftext = "";

        for (var n = 0; n < string.length; n++) {

            var c = string.charCodeAt(n);

            if (c < 128) {
                utftext += String.fromCharCode(c);
            }
            else if((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192);
                utftext += String.fromCharCode((c & 63) | 128);
            }
            else {
                utftext += String.fromCharCode((c >> 12) | 224);
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                utftext += String.fromCharCode((c & 63) | 128);
            }
        }
        return utftext;
    },

    // private method for UTF-8 decoding
    _utf8_decode : function (utftext) {
        var string = "";
        var i = 0;
        var c = c1 = c2 = 0;

        while ( i < utftext.length ) {

            c = utftext.charCodeAt(i);

            if (c < 128) {
                string += String.fromCharCode(c);
                i++;
            }
            else if((c > 191) && (c < 224)) {
                c2 = utftext.charCodeAt(i+1);
                string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
                i += 2;
            }
            else {
                c2 = utftext.charCodeAt(i+1);
                c3 = utftext.charCodeAt(i+2);
                string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
                i += 3;
            }
        }
        return string;
    }
}

var str = 'PYtFLbTaRSeG9qH781zL0d6irQoPYJDFT6ubjfXIAKfQEOXC';
Tests:
Base64 1
Base64.decode(Base64.encode(str))
base64 2
base64.decode(base64.encode(str))
Run results for: Base64 vs. base64

Base64 1

base64 2
