"use strict"; var _obj; function set(target, property, value, receiver) { if (typeof Reflect !== "undefined" && Reflect.set) { set = Reflect.set; } else { set = function set(target, property, value, receiver) { var base = _superPropBase(target, property); var desc; if (base) { desc = Object.getOwnPropertyDescriptor(base, property); if (desc.set) { desc.set.call(receiver, value); return true; } else if (!desc.writable) { return false; } } desc = Object.getOwnPropertyDescriptor(receiver, property); if (desc) { if (!desc.writable) { return false; } desc.value = value; Object.defineProperty(receiver, property, desc); } else { _defineProperty(receiver, property, value); } return true; }; } return set(target, property, value, receiver); } function _set(target, property, value, receiver, isStrict) { const s = set(target, property, value, receiver || target); if (!s && isStrict) { throw new Error('failed to set property'); } return value; } function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; } function _superPropBase(object, property) { while (!Object.prototype.hasOwnProperty.call(object, property)) { object = _getPrototypeOf(object); if (object === null) break; } return object; } function _getPrototypeOf(o) { _getPrototypeOf = Object.getPrototypeOf || function _getPrototypeOf(o) { return o.__proto__; }; return _getPrototypeOf(o); } const Base = {}; const obj = _obj = { set() { return _set(_getPrototypeOf(_obj), "test", 3, this, true); } }; Object.defineProperty(obj, 'test', { value: 2, writable: true, configurable: true, enumerable: false }); Object.setPrototypeOf(obj, Base); expect(obj.set()).toBe(3); expect(Base.test).toBeUndefined(); expect(obj.test).toBe(3); const desc = Object.getOwnPropertyDescriptor(obj, 'test'); expect(desc.configurable).toBe(true); expect(desc.writable).toBe(true); expect(desc.enumerable).toBe(false);