Things that are useful to include in your script file. Some of them are functionalities poly fills from later versions of JavaScript. This also includes json2.js functions (JSON.parse, JSON.stringify) and other useful functions for working with arrays and objects

usefuleIncludes.jsx

    (function includes() {

        (function IncludeIsArray() {
            if (!Array.isArray) {
                Array.isArray = function (arg) {
                    return Object.toString.call(arg) === "[object Array]";
                };
            }
        })();
        (function includeJSON() {
            if (typeof JSON !== "object") {
                JSON = {};
            }

            (function () {
                "use strict";

                var rx_one = /^[\],:{}\s]*$/;
                var rx_two = /\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g;
                var rx_three =
                    /"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g;
                var rx_four = /(?:^|:|,)(?:\s*\[)+/g;
                var rx_escapable =
                    /[\\"\u0000-\u001f\u007f-\u009f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g;
                var rx_dangerous =
                    /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g;

                function f(n) {
                    // Format integers to have at least two digits.
                    return n < 10 ? "0" + n : n;
                }

                function this_value() {
                    return this.valueOf();
                }

                if (typeof Date.toJSON !== "function") {
                    Date.toJSON = function () {
                        return isFinite(this.valueOf()) ?
                            this.getUTCFullYear() +
                            "-" +
                            f(this.getUTCMonth() + 1) +
                            "-" +
                            f(this.getUTCDate()) +
                            "T" +
                            f(this.getUTCHours()) +
                            ":" +
                            f(this.getUTCMinutes()) +
                            ":" +
                            f(this.getUTCSeconds()) +
                            "Z" :
                            null;
                    };

                    Boolean.toJSON = this_value;
                    Number.toJSON = this_value;
                    String.toJSON = this_value;
                }

                var gap;
                var indent;
                var meta;
                var rep;

                function quote(string) {
                    // If the string contains no control characters, no quote characters, and no
                    // backslash characters, then we can safely slap some quotes around it.
                    // Otherwise we must also replace the offending characters with safe escape
                    // sequences.

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

                function str(key, holder) {
                    // Produce a string from holder[key].

                    var i; // The loop counter.
                    var k; // The member key.
                    var v; // The member value.
                    var length;
                    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);
                    }

                    // If we were called with a replacer function, then call the replacer to
                    // obtain a replacement value.

                    if (typeof rep === "function") {
                        value = rep.call(holder, key, value);
                    }

                    // 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);

                        // If the type is "object", we might be dealing with an object or an array or
                        // null.

                        case "object":
                            // 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 (Object.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;
                            }

                            // If the replacer is an array, use it to select the members to be stringified.

                            if (rep && typeof rep === "object") {
                                length = rep.length;
                                for (i = 0; i < length; i += 1) {
                                    if (typeof rep[i] === "string") {
                                        k = rep[i];
                                        v = str(k, value);
                                        if (v) {
                                            partial.push(quote(k) + (gap ? ": " : ":") + v);
                                        }
                                    }
                                }
                            } else {
                                // Otherwise, iterate through all of the keys in the object.

                                for (k in value) {
                                    if (Object.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 ?
                                        "{\n" + gap + partial.join(",\n" + gap) + "\n" + mind + "}" :
                                        "{" + partial.join(",") + "}";
                            gap = mind;
                            return v;
                    }
                }

                // If the JSON object does not yet have a stringify method, give it one.

                if (typeof JSON.stringify !== "function") {
                    meta = {
                        // table of character substitutions
                        "\b": "\\b",
                        "\t": "\\t",
                        "\n": "\\n",
                        "\f": "\\f",
                        "\r": "\\r",
                        '"': '\\"',
                        "\\": "\\\\",
                    };
                    JSON.stringify = function (value, replacer, space) {
                        // The stringify method takes a value and an optional replacer, and an optional
                        // space parameter, and returns a JSON text. The replacer can be a function
                        // that can replace values, or an array of strings that will select the keys.
                        // A Default replacer method can be provided. Use of the space parameter can
                        // produce text that is more easily readable.

                        var i;
                        gap = "";
                        indent = "";

                        // If the space parameter is a number, make an indent string containing that
                        // many spaces.

                        if (typeof space === "number") {
                            for (i = 0; i < space; i += 1) {
                                indent += " ";
                            }

                            // If the space parameter is a string, it will be used as the indent string.
                        } else if (typeof space === "string") {
                            indent = space;
                        }

                        // If there is a replacer, it must be a function or an array.
                        // Otherwise, throw an error.

                        rep = replacer;
                        if (
                            replacer &&
                            typeof replacer !== "function" &&
                            (typeof replacer !== "object" ||
                                typeof replacer.length !== "number")
                        ) {
                            throw new Error("JSON.stringify");
                        }

                        // Make a fake root object containing our value under the key of "".
                        // Return the result of stringifying the value.

                        return str("", {
                            "": value,
                        });
                    };
                }

                // If the JSON object does not yet have a parse method, give it one.

                if (typeof JSON.parse !== "function") {
                    JSON.parse = function (text, reviver) {
                        // The parse method takes a text and an optional reviver function, and returns
                        // a JavaScript value if the text is a valid JSON text.

                        var j;

                        function walk(holder, key) {
                            // The walk method is used to recursively walk the resulting structure so
                            // that modifications can be made.

                            var k;
                            var v;
                            var value = holder[key];
                            if (value && typeof value === "object") {
                                for (k in value) {
                                    if (Object.hasOwnProperty.call(value, k)) {
                                        v = walk(value, k);
                                        if (v !== undefined) {
                                            value[k] = v;
                                        } else {
                                            delete value[k];
                                        }
                                    }
                                }
                            }
                            return reviver.call(holder, key, value);
                        }

                        // Parsing happens in four stages. In the first stage, we replace certain
                        // Unicode characters with escape sequences. JavaScript handles many characters
                        // incorrectly, either silently deleting them, or treating them as line endings.

                        text = String(text);
                        rx_dangerous.lastIndex = 0;
                        if (rx_dangerous.test(text)) {
                            text = text.replace(rx_dangerous, function (a) {
                                return "\\u" + ("0000" + a.charCodeAt(0).toString(16)).slice(-4);
                            });
                        }

                        // In the second stage, we run the text against regular expressions that look
                        // for non-JSON patterns. We are especially concerned with "()" and "new"
                        // because they can cause invocation, and "=" because it can cause mutation.
                        // But just to be safe, we want to reject all unexpected forms.

                        // We split the second stage into 4 regexp operations in order to work around
                        // crippling inefficiencies in IE's and Safari's regexp engines. First we
                        // replace the JSON backslash pairs with "@" (a non-JSON character). Second, we
                        // replace all simple value tokens with "]" characters. Third, we delete all
                        // open brackets that follow a colon or comma or that begin the text. Finally,
                        // we look to see that the remaining characters are only whitespace or "]" or
                        // "," or ":" or "{" or "}". If that is so, then the text is safe for eval.

                        if (
                            rx_one.test(
                                text
                                    .replace(rx_two, "@")
                                    .replace(rx_three, "]")
                                    .replace(rx_four, "")
                            )
                        ) {
                            // In the third stage we use the eval function to compile the text into a
                            // JavaScript structure. The "{" operator is subject to a syntactic ambiguity
                            // in JavaScript: it can begin a block or an object literal. We wrap the text
                            // in parens to eliminate the ambiguity.

                            j = eval("(" + text + ")");

                            // In the optional fourth stage, we recursively walk the new structure, passing
                            // each name/value pair to a reviver function for possible transformation.

                            return typeof reviver === "function" ?
                                walk({
                                    "": j,
                                },
                                    ""
                                ) :
                                j;
                        }

                        // If the text is not JSON parseable, then a SyntaxError is thrown.

                        throw new SyntaxError("JSON.parse");
                    };
                }
            })();
        })();

        function includeJSONCompact() {
            if (!this.JSON) {
                this.JSON = {};
            } (function () {
                function f(n) {
                    return n < 10 ? '0' + n : n;
                }
                if (typeof Date.toJSON !== 'function') {
                    Date.toJSON = function (key) {
                        return isFinite(this.valueOf()) ? this.getUTCFullYear() + '-' + f(this.getUTCMonth() + 1) + '-' + f(this.getUTCDate()) + 'T' + f(this.getUTCHours()) + ':' + f(this.getUTCMinutes()) + ':' + f(this.getUTCSeconds()) + 'Z' : null;
                    };
                    String.toJSON = Number.toJSON = Boolean.toJSON = function (key) {
                        return this.valueOf();
                    };
                }
                var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
                    escapable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
                    gap, indent, meta = {
                        '\b': '\\b',
                        '\t': '\\t',
                        '\n': '\\n',
                        '\f': '\\f',
                        '\r': '\\r',
                        '"': '\\"',
                        '\\': '\\\\'
                    },
                    rep;

                function quote(string) {
                    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 + '"';
                }

                function str(key, holder) {
                    var i, k, v, length, mind = gap,
                        partial, value = holder[key];
                    if (value && typeof value === 'object' && typeof value.toJSON === 'function') {
                        value = value.toJSON(key);
                    }
                    if (typeof rep === 'function') {
                        value = rep.call(holder, key, value);
                    }
                    switch (typeof value) {
                        case 'string':
                            return quote(value);
                        case 'number':
                            return isFinite(value) ? String(value) : 'null';
                        case 'boolean':
                        case 'null':
                            return String(value);
                        case 'object':
                            if (!value) {
                                return 'null';
                            }
                            gap += indent;
                            partial = [];
                            if (Object.toString.apply(value) === '[object Array]') {
                                length = value.length;
                                for (i = 0; i < length; i += 1) {
                                    partial[i] = str(i, value) || 'null';
                                }
                                v = partial.length === 0 ? '[]' : gap ? '[\n' + gap + partial.join(',\n' + gap) + '\n' + mind + ']' : '[' + partial.join(',') + ']';
                                gap = mind;
                                return v;
                            }
                            if (rep && typeof rep === 'object') {
                                length = rep.length;
                                for (i = 0; i < length; i += 1) {
                                    k = rep[i];
                                    if (typeof k === 'string') {
                                        v = str(k, value);
                                        if (v) {
                                            partial.push(quote(k) + (gap ? ': ' : ':') + v);
                                        }
                                    }
                                }
                            } else {
                                for (k in value) {
                                    if (Object.hasOwnProperty.call(value, k)) {
                                        v = str(k, value);
                                        if (v) {
                                            partial.push(quote(k) + (gap ? ': ' : ':') + v);
                                        }
                                    }
                                }
                            }
                            v = partial.length === 0 ? '{}' : gap ? '{\n' + gap + partial.join(',\n' + gap) + '\n' + mind + '}' : '{' + partial.join(',') + '}';
                            gap = mind;
                            return v;
                    }
                }
                if (typeof JSON.stringify !== 'function') {
                    JSON.stringify = function (value, replacer, space) {
                        var i;
                        gap = '';
                        indent = '';
                        if (typeof space === 'number') {
                            for (i = 0; i < space; i += 1) {
                                indent += ' ';
                            }
                        } else if (typeof space === 'string') {
                            indent = space;
                        }
                        rep = replacer;
                        if (replacer && typeof replacer !== 'function' && (typeof replacer !== 'object' || typeof replacer.length !== 'number')) {
                            throw new Error('JSON.stringify');
                        }
                        return str('', {
                            '': value
                        });
                    };
                }
                if (typeof JSON.parse !== 'function') {
                    JSON.parse = function (text, reviver) {
                        var j;

                        function walk(holder, key) {
                            var k, v, value = holder[key];
                            if (value && typeof value === 'object') {
                                for (k in value) {
                                    if (Object.hasOwnProperty.call(value, k)) {
                                        v = walk(value, k);
                                        if (v !== undefined) {
                                            value[k] = v;
                                        } else {
                                            delete value[k];
                                        }
                                    }
                                }
                            }
                            return reviver.call(holder, key, value);
                        }
                        text = String(text);
                        cx.lastIndex = 0;
                        if (cx.test(text)) {
                            text = text.replace(cx, function (a) {
                                return '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
                            });
                        }
                        if (/^[\],:{}\s]*$/.test(text.replace(/\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g, '@').replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']').replace(/(?:^|:|,)(?:\s*\[)+/g, ''))) {
                            j = eval('(' + text + ')');
                            return typeof reviver === 'function' ? walk({
                                '': j
                            }, '') : j;
                        }
                        throw new SyntaxError('JSON.parse');
                    };
                }
            }());
        };

        (function IncludeObjectKeys() {
            if (!Object.keys) {
                Object.keys = (function () {
                    var hasOwnProperty = Object.hasOwnProperty,
                        hasDontEnumBug = !{
                            toString: null,
                        }.propertyIsEnumerable("toString"),
                        dontEnums = [
                            "toString",
                            "toLocaleString",
                            "valueOf",
                            "hasOwnProperty",
                            "isPrototypeOf",
                            "propertyIsEnumerable",
                            "constructor",
                        ],
                        dontEnumsLength = dontEnums.length;

                    return function (obj) {
                        if (
                            (typeof obj !== "object" && typeof obj !== "function") ||
                            obj === null
                        )
                            throw new TypeError("Object.keys called on non-object");

                        var result = [];

                        for (var prop in obj) {
                            if (hasOwnProperty.call(obj, prop)) result.push(prop);
                        }

                        if (hasDontEnumBug) {
                            for (var i = 0; i < dontEnumsLength; i++) {
                                if (hasOwnProperty.call(obj, dontEnums[i]))
                                    result.push(dontEnums[i]);
                            }
                        }
                        return result;
                    };
                })();
            }
        })();
        (function IncludeIndexOf() {
            if (!Array.indexOf) {
                Array.indexOf = function indexOf(member, startFrom) {
                    /* In non-strict mode, if the `this` variable is null or undefined, then it is set to the window object. Otherwise, `this` is automatically converted to an object. In strict mode, if the `this` variable is null or undefined, a `TypeError` is thrown. */
                    if (this == null) {
                        throw new TypeError(
                            "Array.indexOf() - can't convert `" + this + "` to object"
                        );
                    }
                    var index = isFinite(startFrom) ? Math.floor(startFrom) : 0,
                        that = this instanceof Object ? this : new Object(this),
                        length = isFinite(that.length) ? Math.floor(that.length) : 0;
                    if (index >= length) {
                        return -1;
                    }
                    if (index < 0) {
                        index = Math.max(length + index, 0);
                    }
                    if (member === undefined) {
                        /* Since `member` is undefined, keys that don't exist will have the same value as `member`, and thus do need to be checked. */
                        do {
                            if (index in that && that[index] === undefined) {
                                return index;
                            }
                        } while (++index < length);
                    } else {
                        do {
                            if (that[index] === member) {
                                return index;
                            }
                        } while (++index < length);
                    }
                    return -1;
                };
            }
        })();
        (function IncludeLastIndexOf() {
            if (!Array.lastIndexOf) {
                Array.lastIndexOf = function (searchElement /*, fromIndex*/) {
                    'use strict';

                    if (this === void 0 || this === null) {
                        throw new TypeError();
                    }

                    var n, k,
                        t = Object(this),
                        len = t.length >>> 0;
                    if (len === 0) {
                        return -1;
                    }

                    n = len - 1;
                    if (arguments.length > 1) {
                        n = Number(arguments[1]);
                        if (n != n) {
                            n = 0;
                        }
                        else if (n != 0 && n != (1 / 0) && n != -(1 / 0)) {
                            n = (n > 0 || -1) * Math.floor(Math.abs(n));
                        }
                    }

                    for (k = n >= 0 ? Math.min(n, len - 1) : len - Math.abs(n); k >= 0; k--) {
                        if (k in t && t[k] === searchElement) {
                            return k;
                        }
                    }
                    return -1;
                };
            }
        })();
        (function IncludeFilter() {
            /**
                * Array.filter() polyfill
                */
            // From https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter
            if (!Array.filter)
                Array.filter = function (func, thisArg) {
                    "use strict";
                    if (
                        !((typeof func === "Function" || typeof func === "function") && this)
                    )
                        throw new TypeError();

                    var len = this.length >>> 0,
                        res = new Array(len), // preallocate array
                        t = this,
                        c = 0,
                        i = -1;
                    if (thisArg === undefined)
                        while (++i !== len)
                            // checks to see if the key was set
                            if (i in this)
                                if (func(t[i], i, t)) res[c++] = t[i];
                                else
                                    while (++i !== len)
                                        // checks to see if the key was set
                                        if (i in this)
                                            if (func.call(thisArg, t[i], i, t)) res[c++] = t[i];

                    res.length = c; // shrink down array to proper size
                    return res;
                };
        })();

        (function IncludeError() {
            Error.toString = function () {
                if (typeof this.stack === "undefined" || this.stack === null) {
                    this.stack = "placeholder";
                    // The previous line is needed because the next line may indirectly call this method.
                    this.stack = $.stack;
                }
                return "Error";
            };
        });

})();