function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); if (enumerableOnly) symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; }); keys.push.apply(keys, symbols); } return keys; } function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i] != null ? arguments[i] : {}; if (i % 2) { ownKeys(Object(source), true).forEach(function (key) { _defineProperty(target, key, source[key]); }); } else if (Object.getOwnPropertyDescriptors) { Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)); } else { ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } } return target; } 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; } var k = { a: 1, b: 2 }; var o = _objectSpread(_objectSpread({ a: 3 }, k), {}, { b: k.a++ }); var pureA = {}; var pureB = {}; var pureC = {}; var pureD = {}; var pureE = {}; function impureFunc() { console.log('hello'); } var output = _objectSpread(_objectSpread(_objectSpread(_objectSpread(_objectSpread(_objectSpread({}, pureA), {}, { get foo() {}, get bar() {} }, pureB), pureC), impureFunc()), pureD), {}, { pureD }); var simpleOutput = _objectSpread(_objectSpread({}, pureA), {}, { test: '1' }, pureB);