Provides instructions from an API based on simple rules and converts it to Mongo instructions for setting object in database

JsonUtil.js

var JsonUtil = (function (exports) {

    exports = exports || {};

    var reserved = 'userId name'.split(' ');
    var dates = 'updateLastRequestOn'.split(' ');
    var incs = 'newSession'.split(' ');
    var e;
    var isObject;

    function fixUpdate(string) {
        string = string.substr(6);
        return string.charAt(0).toLowerCase() + string.slice(1);
    }

    for (e in reserved) {
        reserved[reserved[e]] = true;
    }

    for (e in dates) {
        dates[dates[e]] = true;
    }

    for (e in incs) {
        incs[incs[e]] = true;
    }

    var toMongo = function (data) {
        var result = { customAttributes: {} };

        var $inc = data.increments;
        delete data.increments;

        var $remove = {};

        var o = {
            customAttributes: data.customAttributes || {}
        };

        for (var n in data) {
            if (dates[n]) {
                n = fixUpdate(n);
                result[n] = Date.now();
            } else if (incs[n]) {
                if (!result.$inc) {
                    result.$inc = {};
                }
                result.$inc[n] = 1;
            } else if (reserved[n]) {
                result[n] = data[n];
            } else {
                isObject = typeof data[n] === 'object';
                if (!isObject) {
                    if(data[n] === '$remove') {
                        $remove[n] = '';
                    } else {
                        o.customAttributes[n] = data[n];
                    }
                }
            }
        }

        // flatten the customAttributes so not to override any
        flatten(o, {}, result);

        if ($inc) {
            result.customAttributes.$inc = $inc;
        }

        result.$unset = $remove;

        return result;
    };

    var flatten = function (source, opts, target) {
        opts = opts || {};

        var delimiter = opts.delimiter || '.';
        target = target || {};

        function step(object, prev) {
            Object.keys(object).forEach(function (key) {
                var value = object[key];
                var isarray = opts.safe && Array.isArray(value);
                var type = Object.prototype.toString.call(value);
                var isobject = (
                    type === '[object Object]' ||
                    type === '[object Array]'
                    );

                var newKey = prev ? prev + delimiter + key : key;

                if (!isarray && isobject) {
                    return step(value, newKey);
                }

                target[newKey] = value;
            });
        }

        step(source);

        return target;
    };

    exports.toMongo = toMongo;
    exports.flatten = flatten;

    return exports;
})();

var data = {
    userId: 1,
    name: 'John Smith',
    email: 'john@mycompany.com',
    updateLastRequestOn: true,
    newSession: true,
    noLongerNeeded: '$remove',
    increments: {
        firstCount: 1,
        secondCount: -2
    },
    bogus: {
        name: 'Nobody'
    }
};

var mongoData = JsonUtil.toMongo(data);
JSON.stringify(mongoData);