getOwnPropertyDescriptor.js

if (!Object.getOwnPropertyDescriptor) {

    Object.getOwnPropertyDescriptor = function getOwnPropertyDescriptor(object, property) {
        if (Object(object) !== object) {
            throw new TypeError('Object.getOwnPropertyDescriptor can only be called on Objects.');
        }

        var descriptor;
        if (!Object.prototype.hasOwnProperty.call(object, property)) {
            return descriptor;
        }

        descriptor = {
            enumerable: Object.prototype.propertyIsEnumerable.call(object, property),
            configurable: true
        };

        descriptor.value = object[property];

        var psPropertyType = object.reflect.find(property).type;
        descriptor.writable = !(psPropertyType === "readonly");

        return descriptor;
    }
}