According to the plan described in #10134, whereas we had to pin these
versions to exactly 7.0.0-beta.55 for Meteor 1.7.0.4, we must now require
at least 7.0.0-beta.56 for Meteor 1.7.1, since other @babel/... packages
used by babel-compiler and meteor-babel are currently at beta.56.
This only affects newly created applications for now, but developers can
update to the latest meteor-node-stubs by running
meteor npm install meteor-node-stubs@latest
https://github.com/meteor/node-stubs/issues/15
While Babel 7 seems to work perfectly well, and the process of upgrading
has been useful, the upgrade is going to require Meteor developers to
update the babel-runtime npm package and their .babelrc plugins, a chore
with which Meteor can't help very much.
On top of that, Babel 7 is still in early beta. I don't want to ship
Meteor 1.6 with a critical component that could change in unexpected ways,
and I don't want to wait for Babel 7 to be finalized to ship Meteor 1.6.
Note that the Meteor command-line tool is still implemented using Babel 7,
which has historically been a great way to gain confidence in
Babel-related changes before pushing them out to all Meteor developers.
@GeoffreyBooth This should take some pressure off the CoffeeScript upgrade
for now. Let's aim for Meteor 1.6.1 for Babel 7 and CoffeeScript 2.0.