var key, x, y, z; // impure key = 1; var _key = key++, { [_key]: { y } } = { 1: { a: 1, y: 1 } }, x = babelHelpers.objectWithoutProperties({ 1: { a: 1, y: 1 } }[_key], ["y"]); expect(x).toEqual({ a: 1 }); expect(key).toBe(2); expect(y).toBe(1); // takes care of the order key = 1; var _$ = { 2: { y: 2, z: 3 }, 3: { y: 2, z: 3 } }, _key2 = ++key, _key3 = ++key, { [_key3]: { y }, [_key2]: { z } } = _$, rest_y = babelHelpers.objectWithoutProperties(_$[_key3], ["y"]), rest_z = babelHelpers.objectWithoutProperties(_$[_key2], ["z"]); expect(y).toBe(2); expect(rest_y).toEqual({ z: 3 }); expect(z).toBe(3); expect(rest_z).toEqual({ y: 2 }); expect(key).toBe(3);