Fixme by @Krinkle on https://gerrit.wikimedia.org/r/#/c/179191/ :

localStorage check is broken. In JavaScript, accessing undeclared variables throws a ReferenceError exception. A boolean cast if-statement is not sufficient.

Either use a typeof check to evaluate the identifier safely, or boolean-cast it as a property of an object (e.g. window, like window.localStorage) which yields the undefined value for undefined properties.

https://www.mediawiki.org/wiki/CC/JS#Type_checks

Change 183830 had a related patch set uploaded (by Amire80):
Check for localStorage availability using window.localStorage

https://gerrit.wikimedia.org/r/183830

Patch-For-Review

Change 183834 had a related patch set uploaded (by Amire80):
Handle unidirectional language pairs in the selector

https://gerrit.wikimedia.org/r/183834

Patch-For-Review

Change 183830 merged by jenkins-bot:
Check for localStorage availability using window.localStorage

https://gerrit.wikimedia.org/r/183830

Change 183834 merged by jenkins-bot:
Handle unidirectional language pairs in the selector

https://gerrit.wikimedia.org/r/183834