Babel preset & cleanup

[zpao]

This revives #127. @yungsters is out for a little while so not going to put this on him.

• Make it so that .js.flow files can also be generated with the preset so project doesn't have to declare any plugins explicitly
• Cleanup some of the dependencies (some were added or moved in the split process, needs a pass)
• Make sure tests are working (Scroll is failing)
• Remove the remaining Babel 5 stuff from fbjs-scripts (will likely just ship 0.7 after this is done with this being the only change).

[zpao]

Ok, rebased everything from the beginning so we shouldn't be introducing any unnecessary deps and un-rearranged the package.jsons for easier diffing (I know, npm did it but it was excruciating to rebase so hopefully I didn't screw that up).

Last but not least, here's the diff of lib/: https://gist.github.com/zpao/5e8d8b2badf781d6c638b42bc56fd862. As you can see the only difference is the .js.flow files for modules using Promise, they are now getting the autorequire transform running. Should probably change that back just to keep fbjs at status quo (it's a 1 line fix in the gulpfile)

[zpao]

Alright, calling this done. Will merge & ship babel-preset-fbjs@1.0.0 and fbjs-scripts@0.7.0 in a few minutes.

cc @kassens

[zertosh]

Is pulling out babel-plugin-syntax-flow too much of a breaking change to do a release of fbjs that's semver compatible with ^0.8.0 (i.e. react@15 compatible)?

Now that babel 6 is compiled with babel 6, the babel family of packages is using babel-runtime@6. In Nuclide we have a top-level babel-runtime@5 (we're stuck with babel@5 for the near-future – because Atom). fbjs, and few other packages we use, have undedupable babel-runtime@6s that nearly doubled our node_modules :( I'm trying to trim it where I can.

[zpao]

Are you talking about fbjs, fbjs-scripts, or babel-preset-fbjs? We aren't using babel-runtime in fbjs itself so presumably you're talking about the preset but you don't have to use that.

[zertosh]

I'm talking about fbjs. You're forced to install babel-runtime via react@15.0.2 -> fbjs@0.8.1 -> babel-plugin-syntax-flow@6.8.0.

└─┬ react@15.0.2
  ├─┬ fbjs@0.8.1
  │ ├─┬ babel-plugin-syntax-flow@6.8.0
  │ │ └─┬ babel-runtime@6.6.1
  │ │   └── core-js@2.3.0
  │ ├── core-js@1.2.6
  ...

I know React doesn't need babel-plugin-syntax-flow or babel-runtime, that's why I'm humbly asking if dcc63b3 can be published as fbjs@0.8.2 (i.e. semver compat with React's dep on fbjs@^0.8.0). I don't know if that'll break any other fbjs consumers https://www.npmjs.com/browse/depended/fbjs.

[zpao]

oooohhh I see. I was confused because that's distinct from this PR :) That should never have been a dependency, I missed it in #121. It's definitely unused and we can publish fbjs@0.8.2 to fix.