Some popular libraries use decorators in their documentation.
Create React App intentionally doesn’t support decorator syntax at the moment because:
- It is an experimental proposal and is subject to change (in fact, it has already changed once, and will change again).
- Most libraries currently support only the old version of the proposal — which will never be a standard.
However in many cases you can rewrite decorator-based code without decorators just as fine.
Please refer to these two threads for reference:
Create React App will add decorator support when the specification advances to a stable stage.