stringify.js

var stringify = (function () {
    var rx_escapable = /[\\\"\u0000-\u001f\u007f-\u009f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g;

    var meta = {
        '\b': '\\b',
        '\t': '\\t',
        '\n': '\\n',
        '\f': '\\f',
        '\r': '\\r',
        '\'': '\\\'',
        '\\': '\\\\'
    };

    function f(n) {
        return n < 10 ? '0' + n : n;
    }

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

    if (typeof Date.prototype.toJSON !== 'function') {
        Date.prototype.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.prototype.toJSON = this_value;
        Number.prototype.toJSON = this_value;
        String.prototype.toJSON = this_value;
    }

    function quote(string) {
        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) {
        var value = holder[key],
            partial,
            length,
            i;

        if (value && typeof value === 'object' && typeof value.toJSON === 'function') {
            value = value.toJSON(key);
        }

        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';
                }

                partial = [];
                if (Object.prototype.toString.apply(value) === '[object Array]') {
                    length = value.length;
                    for (i = 0; i < length; i += 1) {
                        partial[i] = str(i, value) || 'null';
                    }
                    return partial.length === 0 ? '[]' : '[' + partial.join(',') + ']';
                }

                var keys = [];
                for (var k in value) {
                    if (Object.prototype.hasOwnProperty.call(value, k)) {
                        keys.push(k);
                    }
                }

                keys.sort();
                length = keys.length;

                for (i = 0; i < length; i++) {
                    var v = str(keys[i], value);
                    if (v) {
                        partial.push(quote(keys[i]) + ':' + v);
                    }
                }
                return partial.length === 0 ? '{}' : '{' + partial.join(',') + '}';
            default:
                return 'null';
        }
    }

    return function (value) {
        return str('', {
            '': value
        });
    }
})();