feat: update babel to 7

[aminya]

Copied from atom#21623:

Description of the Change

This upgrades babel 5 to babel 7. It targets Electron 11, so we now run modern JavaScript! 🎉

This PR is the result of two years of effort and trying.
I had to fix electron-link so:

• it can support parsing new JavaScript: Use acorn for JS parsing atom/electron-link#20
• it can bundle lazy require Lazy require fix atom/electron-link#27 -> This is merged but not registered. That's why I am using @aminya/electron-link
• and some, other changes

I developed two plugins specifically for Atom to support its special situation:

• babel-preset-atomic this is the plugin that includes all the other babel plugins. It has babel-preset (configured for Electron 6), babel-flow, babel-react, and many of the proposal plugins that are equivalents of the similar plugins included in the deprecated stage-0 package (e.g., class properties, private properties, decorators, private methods, etc.). It adds some of the new proposal plugins, such as optional chaining. It also allows us to do compile-time calculations using codegen and prevel.

See the full list of plugins that babel-preset-atomic has in this package.json.

• babel-plugin-transform-not-strict: this removes 'use strict' whenever 'use babel' (or similar triggers) are used. This is because Babel 6/7 now assumes all the ES modules (those who use import/export) are strict by default. However, this breaks some of the Atom packages because they do non-strict things in ES modules. So, I developed this plugin to remove 'use strict' when the triggers are used. I have baked a feature in this plugin that allows removing 'use strict' selectively by adding 'not strict' directive. Ultimately, we should add this 'not strict' to any file that uses JS loosely in ES modules. An example of this is spec/update-process-env-spec.js

There are two move plugins included for backward compatibility:

• babel-add-module-exports: this plugin circumvents the fact that ES modules export default by "default" keyword. This means we need to call require().default to consume them. This plugin works in combination with transform-not-strict to add module.exports= to the packages that export default things that should have been named exports. For the packages' root, I already made another PR that adds support for both cases, but we cannot patch require for the packages' internal requires as we only have access to the root.

• @babel/plugin-transform-reserved-words that allows the uses of the old banned keywords such as package or debugger.

Fixed the loose usage of JavaScript in the following packages:

• chore: add Eslint to the project + strict JavaScript + fix issues find-and-replace#5

Benefits

This PR has several benefits:

• Allows building Atom with Node 12.16 or above (see this issue). This will be crucial for upgrading Electron.
• This allows using the new babel plugins (e.g., optional chaining) just by including "use babel".
• This also enhances the performance of babel compiling.

Previous attempts

#67
atom#20965

Release Notes

• Updates babel to babel 7 🎉

[DeeDeeG]

If I understand it correctly, this makes newer versions of Node able to build Atom; I think babel 7 has fixes for use with more-recent Node versions.

atom#21091

Affected versions of Node:

• 12.17.0 and newer (can use 12.16.x and older)
• 13.2.0 and newer (can use 13.0.0? I think.)
• 14.0.0 and newer (all versions 14.0.0 and newer are affected).

[aminya]

Yes. Check my comment here: atom#21091 (comment)

[aminya]

I did not notice that we have babel-spec too 😄. I guess I need to update that as well.

[aminya]

Async to generator plugin is not working nicely. I am going to remove it. I also will use our atomic babel preset instead of this whole thing. That is easier to maintain.

[aminya]

NPM's git installer acts weird. Why it can't install some of the packages?!

[DeeDeeG]

FWIW, I believe it clones the git dependency, tries to install the dependency in a temp folder (if there is a package-lock.json checked into the repo of the git dependency, this is used! Not sure why.) and then... throws out everything from the temp folder and just uses the package.json from the git dependency?? Or something? It's a very confusing process.

And as far as I can tell, this causes bizarre errors unique to the CI environment. I can't reproduce the failures locally e.g. when setting apm to be a git dependency.

Have to wonder why it's this complicated for git dependencies, but I supposethe publishing process usually strips oackage-lock.json and similar files... Which isn't the case in a bare git repo? But I would assume package-lock.json would be ingored... 🤷

[DeeDeeG]

Not sure if this will help, but try with npm >= 6.14.2. Their dependency hosted-git-info was bumped a few times with various fixes.

https://github.com/npm/cli/blob/latest/CHANGELOG.md#6142-2020-03-03

[aminya]

This line is causing issues:
https://github.com/atom/atom/blob/4a9d56f52cab00a22744858d4077600d5365197a/packages/incompatible-packages/lib/view-uri.js#L3

I can fix this. We just need to name export it or remove that @babel

[aminya]

Oh wow! Most of the tests have passed! 🎉 The problem was addDefaultProperty option which now I set it to false. We may bring it back later once I updated babel-plugin-add-module-exports in atom-community/babel-plugin-add-module-exports#4

I just need to fix the rest:

##[error] The 'core-render-process for D:/a/1/s/spec/babel-spec.coffee.' test step finished with a non-zero exit code 
 You can run the test again using: 
	 D:/a/1/s/out/Atom Dev x64/atom-dev.exe --resource-path D:\a\1\s --test D:/a/1/s/spec/babel-spec.coffee
##[error] The 'core-render-process for D:/a/1/s/spec/compile-cache-spec.coffee.' test step finished with a non-zero exit code 
 You can run the test again using: 

These tests should actually be updated themselves.

[aminya]

So the problem is that the bundled code cannot find the babel plugins. I am not sure what is happening inside assar when electron-link bundles it. I will switch to babel-preset-atomic and will require it explicitly.

Previously babel-core had all the deps Atom needed for transpiling. But know babel uses separate plugins. So using babel-preset-atomic we can get the same effect.

[aminya]

Including babel dependencies in the snapshot fails. I wonder if we can declare the babel dependencies as external.

[aminya]

I tried 4 different bundlers for bundling babel: https://github.com/atom-ide-community/babel-preset-atomic/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-desc

All of them fail. We need to find a way to declare babel as external, but let Atom call it during normal loading.

[aminya]

This basically works fine now! 🎉

[aminya]

It seems that the find-and-replace package needs some updating.

[aminya]

This is ready! 🎉 I am going to merge this tomorrow.