add experimental babel-plugin-macros support

[kentcdodds]

closes#2730

This will remain undocumented until the brave have tried it in the wild.

Test Plan:

There's currently no established way to test changes to
babel-preset-react-app. But I did create unmaintained-react-scripts-babel-macrosa while back and it worked well.

[kentcdodds]

Copied from the linked issue:

Ok, so, check this out:

unmaintained-react-scripts-babel-macros diff:

(this would be implemented as part of babel-preset-react-app if it becomes official)

App.js

npm test

npm start

So that's pretty rock solid awesome... 😄

Note: that was before the babel-macros -> babel-plugin-macros name change which I did to improve the compatibility with babel 7. There have been no breaking changes other than the name change since I created unmaintained-react-scripts-babel-macros 👍

[omeid]

I understand that it is a massive change but any chance this could land "unsupported" without having to wait for 2.0? Landing it would allow a lot of people to test this actually out in the wild and promote adding macros support to various babel plugins.

[gaearon]

Merged into next.

[Timer]

Support for this has been released in the first v2 alpha version. See #3815 for more details!

[gaearon]

It shipped in 2.0.
https://reactjs.org/blog/2018/10/01/create-react-app-v2.html

[kentcdodds]

This is just awesome! 🎉

[such]

Do you have to eject to make it work?
I've just tried it and I get Error: Cannot find module 'babel-macros'
I tried adding babel-macros and babel-plugin-macros as dependency with no luck...

[kentcdodds]

You're probably trying to use an outdated macro. What are you trying to use?

[such]

I'm trying to use https://github.com/leoasis/graphql-tag.macro

[kentcdodds]

Yeah, that needs to be updated to babel-plugin-macros: https://github.com/leoasis/graphql-tag.macro/blob/47919df7548bd698076cb74fa777874a49bc9bbe/package.json#L20

Luckily the upgrade is pretty simple. Pretty much find/replace babel-macros for babel-plugin-macros.

[such]

ok thanks!