I have just landed an upgrade to ESLint 4 on autoland, this will make
its way to mozilla-central later today.
One thing to note: on upgrading from ESLint 3 to 4, it will clobber your
topsrcdir/node_modules directory - this is intentional to try and avoid
issues we've seen previously with upgrades of npm modules (for npm
ESLint 4 has lots of new features, including glob based configuration
options, and lots of improved rules. We'll be making more use of these
over the next few cycles.
Please consider installing the lint commit/push hooks
if you haven't already.