How do I set the @ababel/parser `decoratorsBeforeExport` plugin option to true?

[HcySunYang]

Describe the bug How do I set the @ababel/parser decoratorsBeforeExport plugin option to true?

To Reproduce

1. Go to https://astexplorer.net/#/gist/39552fa60a6601a59f4b03959f23b4ab/latest
2. See error

Expected behavior Using the export keyword between a decorator and a class is allowed

Screenshots Please: go to https://astexplorer.net/#/gist/39552fa60a6601a59f4b03959f23b4ab/latest

Browser (please complete the following information):

• OS: [e.g. iOS] macOS
• Browser [e.g. chrome, safari] chrome
• Version [e.g. 22] 71.0.3578.98

Additional context