Optional Chaining and null coalescing not working

[rlesniak]

Current behavior
Latest version of Styleguide uses Babel v.7.9.0. Since of v7.8.0 babel supports optional chaining (https://babeljs.io/blog/2020/01/11/7.8.0) but when I use it obj?.prop in styleguide environment app doesnt start and throws error

Module parse failed: Unexpected token (20:36)
File was processed with these loaders:
 * ./node_modules/babel-loader/lib/index.js
You may need an additional loader to handle the result of these loaders.
|   id: getConversationId({
|     appId: conversation.app.id,
>     contactId: conversation.contact?.id
|   }),
|   contactId: conversation.contact?.id,

To reproduce

rlesniak/example@8fdeeac

Expected behavior

Should work with that features

[MoltenCoffee]

I believe this is an issue with Babel via React-docgen, as seen here.
The workaround suggested there (by @mjhenkes ) is to use specific versions of @babel/core and @babel/parser, but that hardly seems like a proper resolution, especially when using styleguidist..

Edit: see this issue as well

[mjhenkes]

+1 My work around is not great.

[sapegin]

We only use Babel to compile Styleguidist code, if you see any warning like this, they are coming from your project.

[MoltenCoffee]

I believe this is not completely true, as it's Babel/ast-types as used by React-docgen. Which still perhaps does not make it an issue with styleguidist necessarily, as it has been present in issues with storybook as well.

However, I do think this is still an issue and shouldn't be closed, but the only fix is for this issue in ast-types to be fixed, react-docgen updating its dependencies and then styleguidist as well.