utils.js

/* eslint camelcase: "off", eqeqeq: "off" */
import Config from './config';

// since es6 imports are static and we run unit tests from the console, window won't be defined when importing this file
var win;
if (typeof(window) === 'undefined') {
    var loc = {
        hostname: ''
    };
    win = {
        navigator: { userAgent: '' },
        document: {
            location: loc,
            referrer: ''
        },
        screen: { width: 0, height: 0 },
        location: loc
    };
} else {
    win = window;
}

/*
 * Saved references to long variable names, so that closure compiler can
 * minimize file size.
 */

var ArrayProto = Array.prototype,
    FuncProto = Function.prototype,
    ObjProto = Object.prototype,
    slice = ArrayProto.slice,
    toString = ObjProto.toString,
    hasOwnProperty = ObjProto.hasOwnProperty,
    windowConsole = win.console,
    navigator = win.navigator,
    document = win.document,
    windowOpera = win.opera,
    screen = win.screen,
    userAgent = navigator.userAgent;

var nativeBind = FuncProto.bind,
    nativeForEach = ArrayProto.forEach,
    nativeIndexOf = ArrayProto.indexOf,
    nativeMap = ArrayProto.map,
    nativeIsArray = Array.isArray,
    breaker = {};

var _ = {
    trim: function(str) {
        // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/Trim#Polyfill
        return str.replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g, '');
    }
};

// Console override
var console = {
    /** @type {function(...*)} */
    log: function() {
        if (Config.DEBUG && !_.isUndefined(windowConsole) && windowConsole) {
            try {
                windowConsole.log.apply(windowConsole, arguments);
            } catch (err) {
                _.each(arguments, function(arg) {
                    windowConsole.log(arg);
                });
            }
        }
    },
    /** @type {function(...*)} */
    warn: function() {
        if (Config.DEBUG && !_.isUndefined(windowConsole) && windowConsole) {
            var args = ['Mixpanel warning:'].concat(_.toArray(arguments));
            try {
                windowConsole.warn.apply(windowConsole, args);
            } catch (err) {
                _.each(args, function(arg) {
                    windowConsole.warn(arg);
                });
            }
        }
    },
    /** @type {function(...*)} */
    error: function() {
        if (Config.DEBUG && !_.isUndefined(windowConsole) && windowConsole) {
            var args = ['Mixpanel error:'].concat(_.toArray(arguments));
            try {
                windowConsole.error.apply(windowConsole, args);
            } catch (err) {
                _.each(args, function(arg) {
                    windowConsole.error(arg);
                });
            }
        }
    },
    /** @type {function(...*)} */
    critical: function() {
        if (!_.isUndefined(windowConsole) && windowConsole) {
            var args = ['Mixpanel error:'].concat(_.toArray(arguments));
            try {
                windowConsole.error.apply(windowConsole, args);
            } catch (err) {
                _.each(args, function(arg) {
                    windowConsole.error(arg);
                });
            }
        }
    }
};

var log_func_with_prefix = function(func, prefix) {
    return function() {
        arguments[0] = '[' + prefix + '] ' + arguments[0];
        return func.apply(console, arguments);
    };
};
var console_with_prefix = function(prefix) {
    return {
        log: log_func_with_prefix(console.log, prefix),
        error: log_func_with_prefix(console.error, prefix),
        critical: log_func_with_prefix(console.critical, prefix)
    };
};


// UNDERSCORE
// Embed part of the Underscore Library
_.bind = function(func, context) {
    var args, bound;
    if (nativeBind && func.bind === nativeBind) {
        return nativeBind.apply(func, slice.call(arguments, 1));
    }
    if (!_.isFunction(func)) {
        throw new TypeError();
    }
    args = slice.call(arguments, 2);
    bound = function() {
        if (!(this instanceof bound)) {
            return func.apply(context, args.concat(slice.call(arguments)));
        }
        var ctor = {};
        ctor.prototype = func.prototype;
        var self = new ctor();
        ctor.prototype = null;
        var result = func.apply(self, args.concat(slice.call(arguments)));
        if (Object(result) === result) {
            return result;
        }
        return self;
    };
    return bound;
};

/**
 * @param {*=} obj
 * @param {function(...*)=} iterator
 * @param {Object=} context
 */
_.each = function(obj, iterator, context) {
    if (obj === null || obj === undefined) {
        return;
    }
    if (nativeForEach && obj.forEach === nativeForEach) {
        obj.forEach(iterator, context);
    } else if (obj.length === +obj.length) {
        for (var i = 0, l = obj.length; i < l; i++) {
            if (i in obj && iterator.call(context, obj[i], i, obj) === breaker) {
                return;
            }
        }
    } else {
        for (var key in obj) {
            if (hasOwnProperty.call(obj, key)) {
                if (iterator.call(context, obj[key], key, obj) === breaker) {
                    return;
                }
            }
        }
    }
};

_.extend = function(obj) {
    _.each(slice.call(arguments, 1), function(source) {
        for (var prop in source) {
            if (source[prop] !== void 0) {
                obj[prop] = source[prop];
            }
        }
    });
    return obj;
};

_.isArray = nativeIsArray || function(obj) {
    return toString.call(obj) === '[object Array]';
};

// from a comment on http://dbj.org/dbj/?p=286
// fails on only one very rare and deliberate custom object:
// var bomb = { toString : undefined, valueOf: function(o) { return "function BOMBA!"; }};
_.isFunction = function(f) {
    try {
        return /^\s*\bfunction\b/.test(f);
    } catch (x) {
        return false;
    }
};

_.isArguments = function(obj) {
    return !!(obj && hasOwnProperty.call(obj, 'callee'));
};

_.toArray = function(iterable) {
    if (!iterable) {
        return [];
    }
    if (iterable.toArray) {
        return iterable.toArray();
    }
    if (_.isArray(iterable)) {
        return slice.call(iterable);
    }
    if (_.isArguments(iterable)) {
        return slice.call(iterable);
    }
    return _.values(iterable);
};

_.map = function(arr, callback, context) {
    if (nativeMap && arr.map === nativeMap) {
        return arr.map(callback, context);
    } else {
        var results = [];
        _.each(arr, function(item) {
            results.push(callback.call(context, item));
        });
        return results;
    }
};

_.keys = function(obj) {
    var results = [];
    if (obj === null) {
        return results;
    }
    _.each(obj, function(value, key) {
        results[results.length] = key;
    });
    return results;
};

_.values = function(obj) {
    var results = [];
    if (obj === null) {
        return results;
    }
    _.each(obj, function(value) {
        results[results.length] = value;
    });
    return results;
};

_.include = function(obj, target) {
    var found = false;
    if (obj === null) {
        return found;
    }
    if (nativeIndexOf && obj.indexOf === nativeIndexOf) {
        return obj.indexOf(target) != -1;
    }
    _.each(obj, function(value) {
        if (found || (found = (value === target))) {
            return breaker;
        }
    });
    return found;
};

_.includes = function(str, needle) {
    return str.indexOf(needle) !== -1;
};

// Underscore Addons
_.inherit = function(subclass, superclass) {
    subclass.prototype = new superclass();
    subclass.prototype.constructor = subclass;
    subclass.superclass = superclass.prototype;
    return subclass;
};

_.isObject = function(obj) {
    return (obj === Object(obj) && !_.isArray(obj));
};

_.isEmptyObject = function(obj) {
    if (_.isObject(obj)) {
        for (var key in obj) {
            if (hasOwnProperty.call(obj, key)) {
                return false;
            }
        }
        return true;
    }
    return false;
};

_.isUndefined = function(obj) {
    return obj === void 0;
};

_.isString = function(obj) {
    return toString.call(obj) == '[object String]';
};

_.isDate = function(obj) {
    return toString.call(obj) == '[object Date]';
};

_.isNumber = function(obj) {
    return toString.call(obj) == '[object Number]';
};

_.isElement = function(obj) {
    return !!(obj && obj.nodeType === 1);
};

_.encodeDates = function(obj) {
    _.each(obj, function(v, k) {
        if (_.isDate(v)) {
            obj[k] = _.formatDate(v);
        } else if (_.isObject(v)) {
            obj[k] = _.encodeDates(v); // recurse
        }
    });
    return obj;
};

_.timestamp = function() {
    Date.now = Date.now || function() {
        return +new Date;
    };
    return Date.now();
};

_.formatDate = function(d) {
    // YYYY-MM-DDTHH:MM:SS in UTC
    function pad(n) {
        return n < 10 ? '0' + n : n;
    }
    return d.getUTCFullYear() + '-' +
        pad(d.getUTCMonth() + 1) + '-' +
        pad(d.getUTCDate()) + 'T' +
        pad(d.getUTCHours()) + ':' +
        pad(d.getUTCMinutes()) + ':' +
        pad(d.getUTCSeconds());
};

_.strip_empty_properties = function(p) {
    var ret = {};
    _.each(p, function(v, k) {
        if (_.isString(v) && v.length > 0) {
            ret[k] = v;
        }
    });
    return ret;
};

/*
 * this function returns a copy of object after truncating it.  If
 * passed an Array or Object it will iterate through obj and
 * truncate all the values recursively.
 */
_.truncate = function(obj, length) {
    var ret;

    if (typeof(obj) === 'string') {
        ret = obj.slice(0, length);
    } else if (_.isArray(obj)) {
        ret = [];
        _.each(obj, function(val) {
            ret.push(_.truncate(val, length));
        });
    } else if (_.isObject(obj)) {
        ret = {};
        _.each(obj, function(val, key) {
            ret[key] = _.truncate(val, length);
        });
    } else {
        ret = obj;
    }

    return ret;
};

_.JSONEncode = (function() {
    return function(mixed_val) {
        var value = mixed_val;
        var quote = function(string) {
            var escapable = /[\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g; // eslint-disable-line no-control-regex
            var meta = { // table of character substitutions
                '\b': '\\b',
                '\t': '\\t',
                '\n': '\\n',
                '\f': '\\f',
                '\r': '\\r',
                '"': '\\"',
                '\\': '\\\\'
            };

            escapable.lastIndex = 0;
            return escapable.test(string) ?
                '"' + string.replace(escapable, function(a) {
                    var c = meta[a];
                    return typeof c === 'string' ? c :
                        '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
                }) + '"' :
                '"' + string + '"';
        };

        var str = function(key, holder) {
            var gap = '';
            var indent = '    ';
            var i = 0; // The loop counter.
            var k = ''; // The member key.
            var v = ''; // The member value.
            var length = 0;
            var mind = gap;
            var partial = [];
            var value = holder[key];

            // If the value has a toJSON method, call it to obtain a replacement value.
            if (value && typeof value === 'object' &&
                typeof value.toJSON === 'function') {
                value = value.toJSON(key);
            }

            // What happens next depends on the value's type.
            switch (typeof value) {
                case 'string':
                    return quote(value);

                case 'number':
                    // JSON numbers must be finite. Encode non-finite numbers as null.
                    return isFinite(value) ? String(value) : 'null';

                case 'boolean':
                case 'null':
                    // If the value is a boolean or null, convert it to a string. Note:
                    // typeof null does not produce 'null'. The case is included here in
                    // the remote chance that this gets fixed someday.

                    return String(value);

                case 'object':
                    // If the type is 'object', we might be dealing with an object or an array or
                    // null.
                    // Due to a specification blunder in ECMAScript, typeof null is 'object',
                    // so watch out for that case.
                    if (!value) {
                        return 'null';
                    }

                    // Make an array to hold the partial results of stringifying this object value.
                    gap += indent;
                    partial = [];

                    // Is the value an array?
                    if (toString.apply(value) === '[object Array]') {
                        // The value is an array. Stringify every element. Use null as a placeholder
                        // for non-JSON values.

                        length = value.length;
                        for (i = 0; i < length; i += 1) {
                            partial[i] = str(i, value) || 'null';
                        }

                        // Join all of the elements together, separated with commas, and wrap them in
                        // brackets.
                        v = partial.length === 0 ? '[]' :
                            gap ? '[\n' + gap +
                            partial.join(',\n' + gap) + '\n' +
                            mind + ']' :
                                '[' + partial.join(',') + ']';
                        gap = mind;
                        return v;
                    }

                    // Iterate through all of the keys in the object.
                    for (k in value) {
                        if (hasOwnProperty.call(value, k)) {
                            v = str(k, value);
                            if (v) {
                                partial.push(quote(k) + (gap ? ': ' : ':') + v);
                            }
                        }
                    }

                    // Join all of the member texts together, separated with commas,
                    // and wrap them in braces.
                    v = partial.length === 0 ? '{}' :
                        gap ? '{' + partial.join(',') + '' +
                        mind + '}' : '{' + partial.join(',') + '}';
                    gap = mind;
                    return v;
            }
        };

        // Make a fake root object containing our value under the key of ''.
        // Return the result of stringifying the value.
        return str('', {
            '': value
        });
    };
})();

/**
 * From https://github.com/douglascrockford/JSON-js/blob/master/json_parse.js
 * Slightly modified to throw a real Error rather than a POJO
 */
_.JSONDecode = (function() {
    var at, // The index of the current character
        ch, // The current character
        escapee = {
            '"': '"',
            '\\': '\\',
            '/': '/',
            'b': '\b',
            'f': '\f',
            'n': '\n',
            'r': '\r',
            't': '\t'
        },
        text,
        error = function(m) {
            var e = new SyntaxError(m);
            e.at = at;
            e.text = text;
            throw e;
        },
        next = function(c) {
            // If a c parameter is provided, verify that it matches the current character.
            if (c && c !== ch) {
                error('Expected \'' + c + '\' instead of \'' + ch + '\'');
            }
            // Get the next character. When there are no more characters,
            // return the empty string.
            ch = text.charAt(at);
            at += 1;
            return ch;
        },
        number = function() {
            // Parse a number value.
            var number,
                string = '';

            if (ch === '-') {
                string = '-';
                next('-');
            }
            while (ch >= '0' && ch <= '9') {
                string += ch;
                next();
            }
            if (ch === '.') {
                string += '.';
                while (next() && ch >= '0' && ch <= '9') {
                    string += ch;
                }
            }
            if (ch === 'e' || ch === 'E') {
                string += ch;
                next();
                if (ch === '-' || ch === '+') {
                    string += ch;
                    next();
                }
                while (ch >= '0' && ch <= '9') {
                    string += ch;
                    next();
                }
            }
            number = +string;
            if (!isFinite(number)) {
                error('Bad number');
            } else {
                return number;
            }
        },

        string = function() {
            // Parse a string value.
            var hex,
                i,
                string = '',
                uffff;
            // When parsing for string values, we must look for " and \ characters.
            if (ch === '"') {
                while (next()) {
                    if (ch === '"') {
                        next();
                        return string;
                    }
                    if (ch === '\\') {
                        next();
                        if (ch === 'u') {
                            uffff = 0;
                            for (i = 0; i < 4; i += 1) {
                                hex = parseInt(next(), 16);
                                if (!isFinite(hex)) {
                                    break;
                                }
                                uffff = uffff * 16 + hex;
                            }
                            string += String.fromCharCode(uffff);
                        } else if (typeof escapee[ch] === 'string') {
                            string += escapee[ch];
                        } else {
                            break;
                        }
                    } else {
                        string += ch;
                    }
                }
            }
            error('Bad string');
        },
        white = function() {
            // Skip whitespace.
            while (ch && ch <= ' ') {
                next();
            }
        },
        word = function() {
            // true, false, or null.
            switch (ch) {
                case 't':
                    next('t');
                    next('r');
                    next('u');
                    next('e');
                    return true;
                case 'f':
                    next('f');
                    next('a');
                    next('l');
                    next('s');
                    next('e');
                    return false;
                case 'n':
                    next('n');
                    next('u');
                    next('l');
                    next('l');
                    return null;
            }
            error('Unexpected "' + ch + '"');
        },
        value, // Placeholder for the value function.
        array = function() {
            // Parse an array value.
            var array = [];

            if (ch === '[') {
                next('[');
                white();
                if (ch === ']') {
                    next(']');
                    return array; // empty array
                }
                while (ch) {
                    array.push(value());
                    white();
                    if (ch === ']') {
                        next(']');
                        return array;
                    }
                    next(',');
                    white();
                }
            }
            error('Bad array');
        },
        object = function() {
            // Parse an object value.
            var key,
                object = {};

            if (ch === '{') {
                next('{');
                white();
                if (ch === '}') {
                    next('}');
                    return object; // empty object
                }
                while (ch) {
                    key = string();
                    white();
                    next(':');
                    if (Object.hasOwnProperty.call(object, key)) {
                        error('Duplicate key "' + key + '"');
                    }
                    object[key] = value();
                    white();
                    if (ch === '}') {
                        next('}');
                        return object;
                    }
                    next(',');
                    white();
                }
            }
            error('Bad object');
        };

    value = function() {
        // Parse a JSON value. It could be an object, an array, a string,
        // a number, or a word.
        white();
        switch (ch) {
            case '{':
                return object();
            case '[':
                return array();
            case '"':
                return string();
            case '-':
                return number();
            default:
                return ch >= '0' && ch <= '9' ? number() : word();
        }
    };

    // Return the json_parse function. It will have access to all of the
    // above functions and variables.
    return function(source) {
        var result;

        text = source;
        at = 0;
        ch = ' ';
        result = value();
        white();
        if (ch) {
            error('Syntax error');
        }

        return result;
    };
})();

_.base64Encode = function(data) {
    var b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
    var o1, o2, o3, h1, h2, h3, h4, bits, i = 0,
        ac = 0,
        enc = '',
        tmp_arr = [];

    if (!data) {
        return data;
    }

    data = _.utf8Encode(data);

    do { // pack three octets into four hexets
        o1 = data.charCodeAt(i++);
        o2 = data.charCodeAt(i++);
        o3 = data.charCodeAt(i++);

        bits = o1 << 16 | o2 << 8 | o3;

        h1 = bits >> 18 & 0x3f;
        h2 = bits >> 12 & 0x3f;
        h3 = bits >> 6 & 0x3f;
        h4 = bits & 0x3f;

        // use hexets to index into b64, and append result to encoded string
        tmp_arr[ac++] = b64.charAt(h1) + b64.charAt(h2) + b64.charAt(h3) + b64.charAt(h4);
    } while (i < data.length);

    enc = tmp_arr.join('');

    switch (data.length % 3) {
        case 1:
            enc = enc.slice(0, -2) + '==';
            break;
        case 2:
            enc = enc.slice(0, -1) + '=';
            break;
    }

    return enc;
};

_.utf8Encode = function(string) {
    string = (string + '').replace(/\r\n/g, '\n').replace(/\r/g, '\n');

    var utftext = '',
        start,
        end;
    var stringl = 0,
        n;

    start = end = 0;
    stringl = string.length;

    for (n = 0; n < stringl; n++) {
        var c1 = string.charCodeAt(n);
        var enc = null;

        if (c1 < 128) {
            end++;
        } else if ((c1 > 127) && (c1 < 2048)) {
            enc = String.fromCharCode((c1 >> 6) | 192, (c1 & 63) | 128);
        } else {
            enc = String.fromCharCode((c1 >> 12) | 224, ((c1 >> 6) & 63) | 128, (c1 & 63) | 128);
        }
        if (enc !== null) {
            if (end > start) {
                utftext += string.substring(start, end);
            }
            utftext += enc;
            start = end = n + 1;
        }
    }

    if (end > start) {
        utftext += string.substring(start, string.length);
    }

    return utftext;
};

_.UUID = (function() {

    // Time/ticks information
    // 1*new Date() is a cross browser version of Date.now()
    var T = function() {
        var d = 1 * new Date(),
            i = 0;

        // this while loop figures how many browser ticks go by
        // before 1*new Date() returns a new number, ie the amount
        // of ticks that go by per millisecond
        while (d == 1 * new Date()) {
            i++;
        }

        return d.toString(16) + i.toString(16);
    };

    // Math.Random entropy
    var R = function() {
        return Math.random().toString(16).replace('.', '');
    };

    // User agent entropy
    // This function takes the user agent string, and then xors
    // together each sequence of 8 bytes.  This produces a final
    // sequence of 8 bytes which it returns as hex.
    var UA = function() {
        var ua = userAgent,
            i, ch, buffer = [],
            ret = 0;

        function xor(result, byte_array) {
            var j, tmp = 0;
            for (j = 0; j < byte_array.length; j++) {
                tmp |= (buffer[j] << j * 8);
            }
            return result ^ tmp;
        }

        for (i = 0; i < ua.length; i++) {
            ch = ua.charCodeAt(i);
            buffer.unshift(ch & 0xFF);
            if (buffer.length >= 4) {
                ret = xor(ret, buffer);
                buffer = [];
            }
        }

        if (buffer.length > 0) {
            ret = xor(ret, buffer);
        }

        return ret.toString(16);
    };

    return function() {
        var se = (screen.height * screen.width).toString(16);
        return (T() + '-' + R() + '-' + UA() + '-' + se + '-' + T());
    };
})();

// _.isBlockedUA()
// This is to block various web spiders from executing our JS and
// sending false tracking data
var BLOCKED_UA_STRS = [
    'ahrefsbot',
    'baiduspider',
    'bingbot',
    'bingpreview',
    'facebookexternal',
    'petalbot',
    'pinterest',
    'screaming frog',
    'yahoo! slurp',
    'yandexbot',

    // a whole bunch of goog-specific crawlers
    // https://developers.google.com/search/docs/advanced/crawling/overview-google-crawlers
    'adsbot-google',
    'apis-google',
    'duplexweb-google',
    'feedfetcher-google',
    'google favicon',
    'google web preview',
    'google-read-aloud',
    'googlebot',
    'googleweblight',
    'mediapartners-google',
    'storebot-google'
];
_.isBlockedUA = function(ua) {
    var i;
    ua = ua.toLowerCase();
    for (i = 0; i < BLOCKED_UA_STRS.length; i++) {
        if (ua.indexOf(BLOCKED_UA_STRS[i]) !== -1) {
            return true;
        }
    }
    return false;
};

/**
 * @param {Object=} formdata
 * @param {string=} arg_separator
 */
_.HTTPBuildQuery = function(formdata, arg_separator) {
    var use_val, use_key, tmp_arr = [];

    if (_.isUndefined(arg_separator)) {
        arg_separator = '&';
    }

    _.each(formdata, function(val, key) {
        use_val = encodeURIComponent(val.toString());
        use_key = encodeURIComponent(key);
        tmp_arr[tmp_arr.length] = use_key + '=' + use_val;
    });

    return tmp_arr.join(arg_separator);
};

_.getQueryParam = function(url, param) {
    // Expects a raw URL

    param = param.replace(/[[]/, '\\[').replace(/[\]]/, '\\]');
    var regexS = '[\\?&]' + param + '=([^&#]*)',
        regex = new RegExp(regexS),
        results = regex.exec(url);
    if (results === null || (results && typeof(results[1]) !== 'string' && results[1].length)) {
        return '';
    } else {
        var result = results[1];
        try {
            result = decodeURIComponent(result);
        } catch(err) {
            console.error('Skipping decoding for malformed query param: ' + result);
        }
        return result.replace(/\+/g, ' ');
    }
};


// _.cookie
// Methods partially borrowed from quirksmode.org/js/cookies.html
_.cookie = {
    get: function(name) {
        var nameEQ = name + '=';
        var ca = document.cookie.split(';');
        for (var i = 0; i < ca.length; i++) {
            var c = ca[i];
            while (c.charAt(0) == ' ') {
                c = c.substring(1, c.length);
            }
            if (c.indexOf(nameEQ) === 0) {
                return decodeURIComponent(c.substring(nameEQ.length, c.length));
            }
        }
        return null;
    },

    parse: function(name) {
        var cookie;
        try {
            cookie = _.JSONDecode(_.cookie.get(name)) || {};
        } catch (err) {
            // noop
        }
        return cookie;
    },

    set_seconds: function(name, value, seconds, is_cross_subdomain, is_secure, is_cross_site, domain_override) {
        var cdomain = '',
            expires = '',
            secure = '';

        if (domain_override) {
            cdomain = '; domain=' + domain_override;
        } else if (is_cross_subdomain) {
            var domain = extract_domain(document.location.hostname);
            cdomain = domain ? '; domain=.' + domain : '';
        }

        if (seconds) {
            var date = new Date();
            date.setTime(date.getTime() + (seconds * 1000));
            expires = '; expires=' + date.toGMTString();
        }

        if (is_cross_site) {
            is_secure = true;
            secure = '; SameSite=None';
        }
        if (is_secure) {
            secure += '; secure';
        }

        document.cookie = name + '=' + encodeURIComponent(value) + expires + '; path=/' + cdomain + secure;
    },

    set: function(name, value, days, is_cross_subdomain, is_secure, is_cross_site, domain_override) {
        var cdomain = '', expires = '', secure = '';

        if (domain_override) {
            cdomain = '; domain=' + domain_override;
        } else if (is_cross_subdomain) {
            var domain = extract_domain(document.location.hostname);
            cdomain = domain ? '; domain=.' + domain : '';
        }

        if (days) {
            var date = new Date();
            date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
            expires = '; expires=' + date.toGMTString();
        }

        if (is_cross_site) {
            is_secure = true;
            secure = '; SameSite=None';
        }
        if (is_secure) {
            secure += '; secure';
        }

        var new_cookie_val = name + '=' + encodeURIComponent(value) + expires + '; path=/' + cdomain + secure;
        document.cookie = new_cookie_val;
        return new_cookie_val;
    },

    remove: function(name, is_cross_subdomain, domain_override) {
        _.cookie.set(name, '', -1, is_cross_subdomain, false, false, domain_override);
    }
};

var _localStorageSupported = null;
var localStorageSupported = function(storage, forceCheck) {
    if (_localStorageSupported !== null && !forceCheck) {
        return _localStorageSupported;
    }

    var supported = true;
    try {
        storage = storage || window.localStorage;
        var key = '__mplss_' + cheap_guid(8),
            val = 'xyz';
        storage.setItem(key, val);
        if (storage.getItem(key) !== val) {
            supported = false;
        }
        storage.removeItem(key);
    } catch (err) {
        supported = false;
    }

    _localStorageSupported = supported;
    return supported;
};

// _.localStorage
_.localStorage = {
    is_supported: function(force_check) {
        var supported = localStorageSupported(null, force_check);
        if (!supported) {
            console.error('localStorage unsupported; falling back to cookie store');
        }
        return supported;
    },

    error: function(msg) {
        console.error('localStorage error: ' + msg);
    },

    get: function(name) {
        try {
            return window.localStorage.getItem(name);
        } catch (err) {
            _.localStorage.error(err);
        }
        return null;
    },

    parse: function(name) {
        try {
            return _.JSONDecode(_.localStorage.get(name)) || {};
        } catch (err) {
            // noop
        }
        return null;
    },

    set: function(name, value) {
        try {
            window.localStorage.setItem(name, value);
        } catch (err) {
            _.localStorage.error(err);
        }
    },

    remove: function(name) {
        try {
            window.localStorage.removeItem(name);
        } catch (err) {
            _.localStorage.error(err);
        }
    }
};

_.register_event = (function() {
    // written by Dean Edwards, 2005
    // with input from Tino Zijdel - crisp@xs4all.nl
    // with input from Carl Sverre - mail@carlsverre.com
    // with input from Mixpanel
    // http://dean.edwards.name/weblog/2005/10/add-event/
    // https://gist.github.com/1930440

    /**
     * @param {Object} element
     * @param {string} type
     * @param {function(...*)} handler
     * @param {boolean=} oldSchool
     * @param {boolean=} useCapture
     */
    var register_event = function(element, type, handler, oldSchool, useCapture) {
        if (!element) {
            console.error('No valid element provided to register_event');
            return;
        }

        if (element.addEventListener && !oldSchool) {
            element.addEventListener(type, handler, !!useCapture);
        } else {
            var ontype = 'on' + type;
            var old_handler = element[ontype]; // can be undefined
            element[ontype] = makeHandler(element, handler, old_handler);
        }
    };

    function makeHandler(element, new_handler, old_handlers) {
        var handler = function(event) {
            event = event || fixEvent(window.event);

            // this basically happens in firefox whenever another script
            // overwrites the onload callback and doesn't pass the event
            // object to previously defined callbacks.  All the browsers
            // that don't define window.event implement addEventListener
            // so the dom_loaded handler will still be fired as usual.
            if (!event) {
                return undefined;
            }

            var ret = true;
            var old_result, new_result;

            if (_.isFunction(old_handlers)) {
                old_result = old_handlers(event);
            }
            new_result = new_handler.call(element, event);

            if ((false === old_result) || (false === new_result)) {
                ret = false;
            }

            return ret;
        };

        return handler;
    }

    function fixEvent(event) {
        if (event) {
            event.preventDefault = fixEvent.preventDefault;
            event.stopPropagation = fixEvent.stopPropagation;
        }
        return event;
    }
    fixEvent.preventDefault = function() {
        this.returnValue = false;
    };
    fixEvent.stopPropagation = function() {
        this.cancelBubble = true;
    };

    return register_event;
})();


var TOKEN_MATCH_REGEX = new RegExp('^(\\w*)\\[(\\w+)([=~\\|\\^\\$\\*]?)=?"?([^\\]"]*)"?\\]$');

_.dom_query = (function() {
    /* document.getElementsBySelector(selector)
    - returns an array of element objects from the current document
    matching the CSS selector. Selectors can contain element names,
    class names and ids and can be nested. For example:

    elements = document.getElementsBySelector('div#main p a.external')

    Will return an array of all 'a' elements with 'external' in their
    class attribute that are contained inside 'p' elements that are
    contained inside the 'div' element which has id="main"

    New in version 0.4: Support for CSS2 and CSS3 attribute selectors:
    See http://www.w3.org/TR/css3-selectors/#attribute-selectors

    Version 0.4 - Simon Willison, March 25th 2003
    -- Works in Phoenix 0.5, Mozilla 1.3, Opera 7, Internet Explorer 6, Internet Explorer 5 on Windows
    -- Opera 7 fails

    Version 0.5 - Carl Sverre, Jan 7th 2013
    -- Now uses jQuery-esque `hasClass` for testing class name
    equality.  This fixes a bug related to '-' characters being
    considered not part of a 'word' in regex.
    */

    function getAllChildren(e) {
        // Returns all children of element. Workaround required for IE5/Windows. Ugh.
        return e.all ? e.all : e.getElementsByTagName('*');
    }

    var bad_whitespace = /[\t\r\n]/g;

    function hasClass(elem, selector) {
        var className = ' ' + selector + ' ';
        return ((' ' + elem.className + ' ').replace(bad_whitespace, ' ').indexOf(className) >= 0);
    }

    function getElementsBySelector(selector) {
        // Attempt to fail gracefully in lesser browsers
        if (!document.getElementsByTagName) {
            return [];
        }
        // Split selector in to tokens
        var tokens = selector.split(' ');
        var token, bits, tagName, found, foundCount, i, j, k, elements, currentContextIndex;
        var currentContext = [document];
        for (i = 0; i < tokens.length; i++) {
            token = tokens[i].replace(/^\s+/, '').replace(/\s+$/, '');
            if (token.indexOf('#') > -1) {
                // Token is an ID selector
                bits = token.split('#');
                tagName = bits[0];
                var id = bits[1];
                var element = document.getElementById(id);
                if (!element || (tagName && element.nodeName.toLowerCase() != tagName)) {
                    // element not found or tag with that ID not found, return false
                    return [];
                }
                // Set currentContext to contain just this element
                currentContext = [element];
                continue; // Skip to next token
            }
            if (token.indexOf('.') > -1) {
                // Token contains a class selector
                bits = token.split('.');
                tagName = bits[0];
                var className = bits[1];
                if (!tagName) {
                    tagName = '*';
                }
                // Get elements matching tag, filter them for class selector
                found = [];
                foundCount = 0;
                for (j = 0; j < currentContext.length; j++) {
                    if (tagName == '*') {
                        elements = getAllChildren(currentContext[j]);
                    } else {
                        elements = currentContext[j].getElementsByTagName(tagName);
                    }
                    for (k = 0; k < elements.length; k++) {
                        found[foundCount++] = elements[k];
                    }
                }
                currentContext = [];
                currentContextIndex = 0;
                for (j = 0; j < found.length; j++) {
                    if (found[j].className &&
                        _.isString(found[j].className) && // some SVG elements have classNames which are not strings
                        hasClass(found[j], className)
                    ) {
                        currentContext[currentContextIndex++] = found[j];
                    }
                }
                continue; // Skip to next token
            }
            // Code to deal with attribute selectors
            var token_match = token.match(TOKEN_MATCH_REGEX);
            if (token_match) {
                tagName = token_match[1];
                var attrName = token_match[2];
                var attrOperator = token_match[3];
                var attrValue = token_match[4];
                if (!tagName) {
                    tagName = '*';
                }
                // Grab all of the tagName elements within current context
                found = [];
                foundCount = 0;
                for (j = 0; j < currentContext.length; j++) {
                    if (tagName == '*') {
                        elements = getAllChildren(currentContext[j]);
                    } else {
                        elements = currentContext[j].getElementsByTagName(tagName);
                    }
                    for (k = 0; k < elements.length; k++) {
                        found[foundCount++] = elements[k];
                    }
                }
                currentContext = [];
                currentContextIndex = 0;
                var checkFunction; // This function will be used to filter the elements
                switch (attrOperator) {
                    case '=': // Equality
                        checkFunction = function(e) {
                            return (e.getAttribute(attrName) == attrValue);
                        };
                        break;
                    case '~': // Match one of space seperated words
                        checkFunction = function(e) {
                            return (e.getAttribute(attrName).match(new RegExp('\\b' + attrValue + '\\b')));
                        };
                        break;
                    case '|': // Match start with value followed by optional hyphen
                        checkFunction = function(e) {
                            return (e.getAttribute(attrName).match(new RegExp('^' + attrValue + '-?')));
                        };
                        break;
                    case '^': // Match starts with value
                        checkFunction = function(e) {
                            return (e.getAttribute(attrName).indexOf(attrValue) === 0);
                        };
                        break;
                    case '$': // Match ends with value - fails with "Warning" in Opera 7
                        checkFunction = function(e) {
                            return (e.getAttribute(attrName).lastIndexOf(attrValue) == e.getAttribute(attrName).length - attrValue.length);
                        };
                        break;
                    case '*': // Match ends with value
                        checkFunction = function(e) {
                            return (e.getAttribute(attrName).indexOf(attrValue) > -1);
                        };
                        break;
                    default:
                        // Just test for existence of attribute
                        checkFunction = function(e) {
                            return e.getAttribute(attrName);
                        };
                }
                currentContext = [];
                currentContextIndex = 0;
                for (j = 0; j < found.length; j++) {
                    if (checkFunction(found[j])) {
                        currentContext[currentContextIndex++] = found[j];
                    }
                }
                // alert('Attribute Selector: '+tagName+' '+attrName+' '+attrOperator+' '+attrValue);
                continue; // Skip to next token
            }
            // If we get here, token is JUST an element (not a class or ID selector)
            tagName = token;
            found = [];
            foundCount = 0;
            for (j = 0; j < currentContext.length; j++) {
                elements = currentContext[j].getElementsByTagName(tagName);
                for (k = 0; k < elements.length; k++) {
                    found[foundCount++] = elements[k];
                }
            }
            currentContext = found;
        }
        return currentContext;
    }

    return function(query) {
        if (_.isElement(query)) {
            return [query];
        } else if (_.isObject(query) && !_.isUndefined(query.length)) {
            return query;
        } else {
            return getElementsBySelector.call(this, query);
        }
    };
})();

_.info = {
    campaignParams: function() {
        var campaign_keywords = 'utm_source utm_medium utm_campaign utm_content utm_term'.split(' '),
            kw = '',
            params = {};
        _.each(campaign_keywords, function(kwkey) {
            kw = _.getQueryParam(document.URL, kwkey);
            if (kw.length) {
                params[kwkey] = kw;
            }
        });

        return params;
    },

    searchEngine: function(referrer) {
        if (referrer.search('https?://(.*)google.([^/?]*)') === 0) {
            return 'google';
        } else if (referrer.search('https?://(.*)bing.com') === 0) {
            return 'bing';
        } else if (referrer.search('https?://(.*)yahoo.com') === 0) {
            return 'yahoo';
        } else if (referrer.search('https?://(.*)duckduckgo.com') === 0) {
            return 'duckduckgo';
        } else {
            return null;
        }
    },

    searchInfo: function(referrer) {
        var search = _.info.searchEngine(referrer),
            param = (search != 'yahoo') ? 'q' : 'p',
            ret = {};

        if (search !== null) {
            ret['$search_engine'] = search;

            var keyword = _.getQueryParam(referrer, param);
            if (keyword.length) {
                ret['mp_keyword'] = keyword;
            }
        }

        return ret;
    },

    /**
     * This function detects which browser is running this script.
     * The order of the checks are important since many user agents
     * include key words used in later checks.
     */
    browser: function(user_agent, vendor, opera) {
        vendor = vendor || ''; // vendor is undefined for at least IE9
        if (opera || _.includes(user_agent, ' OPR/')) {
            if (_.includes(user_agent, 'Mini')) {
                return 'Opera Mini';
            }
            return 'Opera';
        } else if (/(BlackBerry|PlayBook|BB10)/i.test(user_agent)) {
            return 'BlackBerry';
        } else if (_.includes(user_agent, 'IEMobile') || _.includes(user_agent, 'WPDesktop')) {
            return 'Internet Explorer Mobile';
        } else if (_.includes(user_agent, 'SamsungBrowser/')) {
            // https://developer.samsung.com/internet/user-agent-string-format
            return 'Samsung Internet';
        } else if (_.includes(user_agent, 'Edge') || _.includes(user_agent, 'Edg/')) {
            return 'Microsoft Edge';
        } else if (_.includes(user_agent, 'FBIOS')) {
            return 'Facebook Mobile';
        } else if (_.includes(user_agent, 'Chrome')) {
            return 'Chrome';
        } else if (_.includes(user_agent, 'CriOS')) {
            return 'Chrome iOS';
        } else if (_.includes(user_agent, 'UCWEB') || _.includes(user_agent, 'UCBrowser')) {
            return 'UC Browser';
        } else if (_.includes(user_agent, 'FxiOS')) {
            return 'Firefox iOS';
        } else if (_.includes(vendor, 'Apple')) {
            if (_.includes(user_agent, 'Mobile')) {
                return 'Mobile Safari';
            }
            return 'Safari';
        } else if (_.includes(user_agent, 'Android')) {
            return 'Android Mobile';
        } else if (_.includes(user_agent, 'Konqueror')) {
            return 'Konqueror';
        } else if (_.includes(user_agent, 'Firefox')) {
            return 'Firefox';
        } else if (_.includes(user_agent, 'MSIE') || _.includes(user_agent, 'Trident/')) {
            return 'Internet Explorer';
        } else if (_.includes(user_agent, 'Gecko')) {
            return 'Mozilla';
        } else {
            return '';
        }
    },

    /**
     * This function detects which browser version is running this script,
     * parsing major and minor version (e.g., 42.1). User agent strings from:
     * http://www.useragentstring.com/pages/useragentstring.php
     */
    browserVersion: function(userAgent, vendor, opera) {
        var browser = _.info.browser(userAgent, vendor, opera);
        var versionRegexs = {
            'Internet Explorer Mobile': /rv:(\d+(\.\d+)?)/,
            'Microsoft Edge': /Edge?\/(\d+(\.\d+)?)/,
            'Chrome': /Chrome\/(\d+(\.\d+)?)/,
            'Chrome iOS': /CriOS\/(\d+(\.\d+)?)/,
            'UC Browser' : /(UCBrowser|UCWEB)\/(\d+(\.\d+)?)/,
            'Safari': /Version\/(\d+(\.\d+)?)/,
            'Mobile Safari': /Version\/(\d+(\.\d+)?)/,
            'Opera': /(Opera|OPR)\/(\d+(\.\d+)?)/,
            'Firefox': /Firefox\/(\d+(\.\d+)?)/,
            'Firefox iOS': /FxiOS\/(\d+(\.\d+)?)/,
            'Konqueror': /Konqueror:(\d+(\.\d+)?)/,
            'BlackBerry': /BlackBerry (\d+(\.\d+)?)/,
            'Android Mobile': /android\s(\d+(\.\d+)?)/,
            'Samsung Internet': /SamsungBrowser\/(\d+(\.\d+)?)/,
            'Internet Explorer': /(rv:|MSIE )(\d+(\.\d+)?)/,
            'Mozilla': /rv:(\d+(\.\d+)?)/
        };
        var regex = versionRegexs[browser];
        if (regex === undefined) {
            return null;
        }
        var matches = userAgent.match(regex);
        if (!matches) {
            return null;
        }
        return parseFloat(matches[matches.length - 2]);
    },

    os: function() {
        var a = userAgent;
        if (/Windows/i.test(a)) {
            if (/Phone/.test(a) || /WPDesktop/.test(a)) {
                return 'Windows Phone';
            }
            return 'Windows';
        } else if (/(iPhone|iPad|iPod)/.test(a)) {
            return 'iOS';
        } else if (/Android/.test(a)) {
            return 'Android';
        } else if (/(BlackBerry|PlayBook|BB10)/i.test(a)) {
            return 'BlackBerry';
        } else if (/Mac/i.test(a)) {
            return 'Mac OS X';
        } else if (/Linux/.test(a)) {
            return 'Linux';
        } else if (/CrOS/.test(a)) {
            return 'Chrome OS';
        } else {
            return '';
        }
    },

    device: function(user_agent) {
        if (/Windows Phone/i.test(user_agent) || /WPDesktop/.test(user_agent)) {
            return 'Windows Phone';
        } else if (/iPad/.test(user_agent)) {
            return 'iPad';
        } else if (/iPod/.test(user_agent)) {
            return 'iPod Touch';
        } else if (/iPhone/.test(user_agent)) {
            return 'iPhone';
        } else if (/(BlackBerry|PlayBook|BB10)/i.test(user_agent)) {
            return 'BlackBerry';
        } else if (/Android/.test(user_agent)) {
            return 'Android';
        } else {
            return '';
        }
    },

    referringDomain: function(referrer) {
        var split = referrer.split('/');
        if (split.length >= 3) {
            return split[2];
        }
        return '';
    },

    properties: function() {
        return _.extend(_.strip_empty_properties({
            '$os': _.info.os(),
            '$browser': _.info.browser(userAgent, navigator.vendor, windowOpera),
            '$referrer': document.referrer,
            '$referring_domain': _.info.referringDomain(document.referrer),
            '$device': _.info.device(userAgent)
        }), {
            '$current_url': win.location.href,
            '$browser_version': _.info.browserVersion(userAgent, navigator.vendor, windowOpera),
            '$screen_height': screen.height,
            '$screen_width': screen.width,
            'mp_lib': 'web',
            '$lib_version': Config.LIB_VERSION,
            '$insert_id': cheap_guid(),
            'time': _.timestamp() / 1000 // epoch time in seconds
        });
    },

    people_properties: function() {
        return _.extend(_.strip_empty_properties({
            '$os': _.info.os(),
            '$browser': _.info.browser(userAgent, navigator.vendor, windowOpera)
        }), {
            '$browser_version': _.info.browserVersion(userAgent, navigator.vendor, windowOpera)
        });
    },

    pageviewInfo: function(page) {
        return _.strip_empty_properties({
            'mp_page': page,
            'mp_referrer': document.referrer,
            'mp_browser': _.info.browser(userAgent, navigator.vendor, windowOpera),
            'mp_platform': _.info.os()
        });
    }
};

var cheap_guid = function(maxlen) {
    var guid = Math.random().toString(36).substring(2, 10) + Math.random().toString(36).substring(2, 10);
    return maxlen ? guid.substring(0, maxlen) : guid;
};

// naive way to extract domain name (example.com) from full hostname (my.sub.example.com)
var SIMPLE_DOMAIN_MATCH_REGEX = /[a-z0-9][a-z0-9-]*\.[a-z]+$/i;
// this next one attempts to account for some ccSLDs, e.g. extracting oxford.ac.uk from www.oxford.ac.uk
var DOMAIN_MATCH_REGEX = /[a-z0-9][a-z0-9-]+\.[a-z.]{2,6}$/i;
/**
 * Attempts to extract main domain name from full hostname, using a few blunt heuristics. For
 * common TLDs like .com/.org that always have a simple SLD.TLD structure (example.com), we
 * simply extract the last two .-separated parts of the hostname (SIMPLE_DOMAIN_MATCH_REGEX).
 * For others, we attempt to account for short ccSLD+TLD combos (.ac.uk) with the legacy
 * DOMAIN_MATCH_REGEX (kept to maintain backwards compatibility with existing Mixpanel
 * integrations). The only _reliable_ way to extract domain from hostname is with an up-to-date
 * list like at https://publicsuffix.org/ so for cases that this helper fails at, the SDK
 * offers the 'cookie_domain' config option to set it explicitly.
 * @example
 * extract_domain('my.sub.example.com')
 * // 'example.com'
 */
var extract_domain = function(hostname) {
    var domain_regex = DOMAIN_MATCH_REGEX;
    var parts = hostname.split('.');
    var tld = parts[parts.length - 1];
    if (tld.length > 4 || tld === 'com' || tld === 'org') {
        domain_regex = SIMPLE_DOMAIN_MATCH_REGEX;
    }
    var matches = hostname.match(domain_regex);
    return matches ? matches[0] : '';
};

var JSONStringify = null, JSONParse = null;
if (typeof JSON !== 'undefined') {
    JSONStringify = JSON.stringify;
    JSONParse = JSON.parse;
}
JSONStringify = JSONStringify || _.JSONEncode;
JSONParse = JSONParse || _.JSONDecode;

// EXPORTS (for closure compiler)
_['toArray']                = _.toArray;
_['isObject']               = _.isObject;
_['JSONEncode']             = _.JSONEncode;
_['JSONDecode']             = _.JSONDecode;
_['isBlockedUA']            = _.isBlockedUA;
_['isEmptyObject']          = _.isEmptyObject;
_['info']                   = _.info;
_['info']['device']         = _.info.device;
_['info']['browser']        = _.info.browser;
_['info']['browserVersion'] = _.info.browserVersion;
_['info']['properties']     = _.info.properties;

export {
    _,
    userAgent,
    console,
    win as window,
    document,
    navigator,
    cheap_guid,
    console_with_prefix,
    extract_domain,
    localStorageSupported,
    JSONStringify,
    JSONParse,
    slice
};