Determine mechanism to add plugins after `babel-preset-env` plugins.

Currently, all user supplied plugins (in options.babel.plugins) are added before the babel-preset-env plugins (see final plugin construction code here). I believe that this is the correct default position for all plugins (as most want to operate on the raw source AST).

However, there are some circumstances where you want to write plugins that operate on the AST after the various babel transforms have occurred. The prime example of this is the babel6-plugin-strip-class-callcheck plugin, which removes the _classCallCheck for production code (which is used by ember-data).

I can think of a couple of possible solutions here, we just need to decide what to implement.

• Option A: this emulates babel@5’s setup (which would have { transformer: ***, position: 'after' }).

this.options.babel.plugins.push({
  plugin: require('babel6-plugin-strip-class-callcheck'),
  postion: 'after'
});

• Option B

this.options.babel.pluginsAfterTransformation = [
  require('babel6-plugin-strip-class-callcheck')
];

I’m sure there are additional options, and I’m happy for suggestions.

[rwjblue]

what would be the resulting order then?

• plugins
• AMD modules plugin
• preset-env
• pluginsAfterTransformation (or better name)

[rwjblue]

Modules are processed before the rest of preset env at the moment (I’m open to changing that if y’all disagree). So I don’t really think we are offering any options other than before or after preset env.

I looked into using a DAG last night, and it would be easy enough to implement but there isn’t a defining property we could use for the before/after (e.g. Babel plugins don’t have a name property). Which means it would be very difficult…