The modules test app appears to be running with process.env.NODE_ENV equal
to "production" on Circle CI: https://circleci.com/gh/meteor/meteor/5030.
Enabling this transform in production as well as development is fine
because we primarily want to test that plugins from the "env" section of
.babelrc are respected, regardless of the value of process.env.NODE_ENV.
Using different plugins in production might be worth testing, too, but
that's less critical.
Follow-up to #8963.
As proposed here: https://github.com/rollup/rollup/wiki/pkg.module
By supporting ECMAScript module entry points for npm packages in Meteor
1.5, we will be well-positioned to do more effective import/export-based
tree shaking in future versions of Meteor.
We can't do the same thing on the server because we can't change how
native Node resolves package entry points based on the "main" field of the
package.json module.
On the other hand, all npm packages have to work in Node using the "main"
field, and client bundles stand to benefit the most from tree shaking, so
this client/server difference should not be problematic.
Note that the "jsnext:main" property is also supported as a legacy synonym
for "module".
Generally, module.prefetch(id) will not throw even if the fetched module
is missing. If you need to know whether module.prefetch(id) succeeded,
simply await the result of the promise, which will be null on success, or
an Error object if the module could not be imported.
This polyfill is unnecessary in Node, and added a whopping 22KB to the
minified client bundle. If you really need the Buffer API on the client,
you can get it from require("buffer").Buffer.
This should elegantly address the issues described in this comment:
https://github.com/meteor/meteor/pull/8327#issuecomment-280881830
I toyed with the possibility of turning package variables (both imports
from other packages and intercepted "global" variable assignments) into
properties on a shared namespace object, but that would have been a major
breaking change for existing package code, because it would have required
automatically rewriting variable references in package modules.
