Support for external deps

[xtuc]

Following the discussion from babel/website#1302.

It would be great to allow externals for both Browserify and Rollup. What do you think @Rich-Harris?

PS: i'm working on it

[xtuc]

Imagine I want to dedupe babel-types (babel-plugin-ivi-jsx is requiring it):

<script type="text/javascript" src="http://localhost:9000/babel-types"></script>
<script type="text/javascript" src="http://localhost:9000/babel-plugin-ivi-jsx"></script>

When I declare babel-types as an external dependency, browserify fails at runtime with Cannot find module 'babel-types'. In the page babel-types is a available as window.babelTypes. I don't know how to tell browserify to use it.

Maybe we could generate a fake package called babel-types somehow which just contains a alias statement: module.exports = window.babelTypes but sounds hacky and fragile.

Do you have an idea?

[Daniel15]

What about allowing externals to be passed as querystring parameters? For example /babel-plugin-ivi-jsx?externals[babel-types]=babelTypes could do the equivalent of doing this in a Webpack config:

externals: {
  'babel-types': 'babelTypes',
}

[xtuc]

Yeah, configuration is only possible through query parameters (because of the CDN).

I planned something like this: /babel-plugin-ivi-jsx?externals=babel-types,babel-core.

I don't get how browserify is working with externals, they are not passed as arguments as with Rollup. Maybe @Rich-Harris could help us here.

[Rich-Harris]

This seems like a good. Afraid I have no idea how to make it work with Browserify! 😬

[ceremcem]

Our project is using browserify, you may want to take a look at the gulpfile. My two cents...

[xtuc]

We need this for the Babel REPL. Since Browserify is only used as a fallback, I think it's fine to support externals only when you bundle with Rollup (and your module supports it).

[xtuc]

Well now we have a PR #37 but I don't get it, it can't work. If someone has the time to look at it 🙏