Remove @babel/plugin-proposal-object-rest-spread from default babel configuration

Is your proposal related to a problem?

This has been suggested in other issues (notably #5310) and pull requests (#5331). The pull request was closed with the comment:

Unfortunately, I still don’t trust that this works correctly. There’s zero harm in including this plugin to be safe, so let’s leave it for now.

There are a couple of places where this causes “harm”:

• I am declaring Javascript expressions as parameters to higher order components, and these expressions are serialized and sent to the server. The object rest spread babel plugin injects a function call when using the rest operator in these expressions, causing them to fail to be interpreted and validated on the server.
• Perhaps more relevant to more people, transforming this code can cause additional debugging pain. This is not a trivial issue.

The addition of the browsers option to package.json is awesome. I’ve been craving a “leave my code the $#@& alone” setting, and setting development mode to latest chrome is almost that, except for the rest operator, and it’s a pain!

Describe the solution you’d like

Remove the inclusion of the @babel/plugin-proposal-object-rest-spread package by default. https://github.com/facebook/create-react-app/blob/bffc296a2c8967d46bed40d3120d82f2752496dc/packages/babel-preset-react-app/create.js#L161

Describe alternatives you’ve considered

The obvious workaround is to use Object.assign, but this is an unnecessary restriction and prevents me from using a productive language feature.

[danderson00]

I’ve discovered another subtle and frustrating side effect of this. If you import a CommonJS module from an ES6 module and the CommonJS module contains the object spread operator, the app throws at runtime with the below error:

Attempted import error: ‘./path’ does not contain a default export (imported as ‘name’)

It’s a pain if you’re sharing modules between node and the browser. Again, the workaround is to use Object.assign, so it’s not the end of the world, but… Rar.

[heyimalex]

Not sure how relevant this is, but on the babel releases page there appear to have been a few changes to this plugin recently, so removing this would probably coincide with bumping the version of babel we pin. I understand your reasoning, but it’s tough for me to really judge the stability.