Flatten javascript objects into a single-depth object

Object Flatten

/**
 * Flattens a json object into a single-dimensional representation
 * @param: stripPrefix: boolean
 *  by default, subobjects will have their property name prefixed to the flattened property name.
 *  This is done to prevent overwriting of properties with the same name.  If this is a non-issue
 *  for your data type, then feel free to set this to true
 * @return: a single dimensional copy of the original object
 */
Object.defineProperty(Object.prototype, 'flatten', {
    value: function(stripPrefix) {
        var toReturn = {};

        for (var i in this) {
            if (!this.hasOwnProperty(i)) continue;

            if ((typeof this[i]) == 'object' && this[i] != null) {
                var obj = this[i];
                var flatObject = obj.flatten();
                for (var x in flatObject) {
                    if (!flatObject.hasOwnProperty(x)) continue;

                    var prefix = (stripPrefix == true) ? x : `${i}.${x}`;
                    toReturn[prefix] = flatObject[x];
                }
            } else {
                toReturn[i] = this[i];
            }
        }
        return toReturn;
    },
    writable: false,
    configurable: false,
    enumerable: false
});