add .babelrc to .npmignore

[orzechowskid]

babel applies whatever config is closest to any given source file, meaning a .babelrc provided by this NPM package will overrule a .babelrc belonging to consumers of this package (who may desire or require different presets and plugins for their app).

[MatthewHerbst]

Hi @orzechowskid thanks for the PR. The lookup behavior for the .babelrc file searches up to the package root of the current package. react-waypoint will never be in the package root, but in ./node_modules relative to the root. As such, the .babelrc in this repo will never override consumer .babelrcs. Further, we need the .babelrc in this repo to ensure that we can build react-waypoint properly for end-consumers.

Learn more here:
https://babeljs.io/docs/en/babelrc.html#lookup-behavior

[orzechowskid]

The PR isn't to remove babel config from the Git repo; it's to remove babel config from the package archive pushed to NPM. I understand that .babelrc is required for development purposes - that's why a change was made to .npmignore instead of .gitignore .

When consumers attempt to transpile an app with react-waypoint as an ES2015 module dependency, the babel config at myproject/node_modules/react-waypoint/.babelrc will be applied instead of the intended myproject/.babelrc, which is exactly what https://babeljs.io/docs/en/babelrc.html#lookup-behavior describes:

Babel will look for a .babelrc in the current directory of the file being transpiled. If one does not exist, it will travel up the directory tree until it finds either a .babelrc, or a package.json with a "babel": {} hash within.

And that's exactly what's happening to me, because what you refer to as the "current package" is not react-waypoint, it's my app. react-waypoint is complaining that babel-preset-airbnb isn't installed:

 error  in ./node_modules/react-waypoint/es/index.js

Module build failed (from ./node_modules/babel-loader/lib/index.js):
Error: Couldn't find preset "airbnb" relative to directory "/home/dorzechowski/repos/ui-react/node_modules/react-waypoint"
    at /home/dorzechowski/repos/ui-react/node_modules/babel-core/lib/transformation/file/options/option-manager.js:293:19
    at Array.map (<anonymous>)
    etc. etc. etc. etc.

...which is true; I don't have that preset installed. That preset, I'm assuming, is needed to build react-waypoint for use in whatever runtimes it supports. No argument there. But It's not needed to transpile react-waypoint code for use on the targets supported by my app. And indeed, removing node_modules/react-waypoint/.babelrc allows transpilation to succeed, and a smoke test shows react-waypoint behaving normally.

I hope you'll at least consider re-opening this PR; it's awesome that you're publishing this package with a module field and providing ES2015 source files, but kind of a bummer that I have to install otherwise-unneeded babel things to consume those files.

(and either way, thanks for the good work on this lib - we use it in a bunch of places and it's really come in handy)

cheers

[MatthewHerbst]

Sorry, I did mistakenly think you had made the commit to .gitignore. I deeply apologize for my haste.

That preset, I'm assuming, is needed to build react-waypoint for use in whatever runtimes it supports. No argument there. But It's not needed to transpile react-waypoint code for use on the targets supported by my app.

Would making this change potentially impact users who do need it to transpile for all those other targets? I wonder if the real issue might be that we are missing a peerDependency?

[orzechowskid]

no worries! sorry then for explaining to you a bunch of stuff you probably already knew :)

I think that for other projects to successfully transpile node_modules/react-waypoint/es/index.js , they must already be using babel-preset-airbnb and babel-plugin-transform-react-remove-prop-types in their own babel config or else they'd encounter the same error I described above. So they're already set up appropriately, which means there's no impact, and merging this would not be a breaking change requiring a major version bump.

What are you thinking about as a peerDependency, and to which package do you see it being applied? I can't see what a peerDependency would do for anyone here that the existing devDependency entries don't. That plugin and preset are correctly listed as devDependencies of react-waypoint since your source is ES2015+ and your output looks like ES5.

[realityking]

For what it's worth, I agree with adding .babelrc to .gitignore. This package contains the already babelified code anyway, so there's no need to impose this package's babel settings on downstream users who might want to do additional processing.

[trotzig]

This looks reasonable to me. Thanks!

[trotzig]

This PR was included in the 8.1.0 release.