CLI Project Generator: Explicitly include a default .babelrc

[namuol]

Motivation

React Native projects nested inside babel-enabled projects can break unexpectedly due to misconfigured .babelrc in the parent project.

See #7821 for details.

Test plan

Added a simple check to ensure the generator provides a .babelrc file by default.

[ghost]

By analyzing the blame information on this pull request, we identified @ide and @skevy to be potential reviewers.

[janicduplessis]

Tests are failing on node 4 (npm 2). I think you have to add "babel-preset-react-native" to package.json for the generated project. It works on npm 3 because of flattened dependencies.

[ghost]

@namuol updated the pull request.

[ghost]

@namuol updated the pull request.

[ghost]

It's been a while since the last commit was reviewed and the labels show this pull request needs review. Based on the blame information for the files in this pull request we identified @bestander as a potential reviewer. Could you take a look please or cc someone with more context?

[bestander]

babel-preset-react-native may become incompatible with the one react-native is using when the project gets updated so I am not 100% happy about adding a new peer dependency in react-native-cli.

Can we do to babel-preset-react-native the same thing we do to react on local-cli?

[bestander]

Sorry for delay :)

[mkonicek]

Based on @bestander's last comment I think we should close this and revisit later if needed.

Thanks for the contribution and caring about improving tests!

[tgoldenberg]

So after looking at the related issue #7821, I think there must be an easy solution here. It sounds like @mkonicek doesn't want to modify the peer dependencies on initialization, so here's what I propose:

What if we keep the default .babelrc file with {"presets": ["react-native"] }, but not include a peer dependency of babel-preset-react-native? The caveat to this is that it would throw an error on npm 2, but couldn't we also make a minimum version of npm to use, and include that in the Getting Started docs?

I don't think the issue should be ignored, though. There is precedent in create-react-app, for example, of addressing the issue of confusing behavior due to babel searching parent directories (link).

Sorry if I'm being naive here, this is the first RN issue I've actively worked on. I also have a forked version without the peer dependency changes at https://github.com/tgoldenberg/react-native. @janicduplessis @namuol what do you think?