兼容性列表

	Chrome	Firefox	IE	Edge	Opera	Safari
Object.assign	45	34 (34)	❎	✅	32	9
Element.classList	8.0	3.6 (1.9.2)	10	✅	11.50	5.1

Polyfill使用core-js, https://github.com/zloirock/core-js.