新的设计改了很多语义，比如你不能在装饰器里拿到原型，也不能在类装饰器里拿到属性 /方法装饰器的数据，最重要的是，不能改变成员的属性，你不再能把属性变 getter setter ，也不能增加删除成员
基本上和 ts 的装饰器不一样了，现在 tc39 的态度就是不应该在严肃项目里用现有的装饰器
Babel 7 supports the decorators proposal presented to TC39 in the November 2018 TC39 meeting. It's fine to use these for experimental purposes, but they face significant performance issues, are not yet widely adopted; we don't plan to continue pushing for this proposal in TC39. As such, we recommend against using this version for serious work. In follow-on proposals to add more built-in decorators, we hope to be able to recover the extra functionality that the November 2018 decorators proposal supported.