Magento2 localisation Javascript

Not sure if you figured it out already, but I thought I'd answer anyway..

I guess the other answers are heading in the right direction.

Assuming you already have the translations installed, if not please:

bin/magento i18n:pack -m replace -d source_nl_NL.csv . nl_NL

So, first of all, please clear the cache(as others suggested as well):

rm -rf var/cache var/generation var/page_cache var/view_preprocessed

Secondly, please clear your pub/static folder:

rm -rf pub/static/*/

Then we regenerate the static-content: (I missed the langcode in the other answers..)

bin/magento setup:static-content:deploy nl_NL - Make sure you add the langcode

Now check if there were any js-translation.json created:

find pub/static/ -name "js-translation.json"

Most likely you'll get a list of js-translation.json files. Please check these files and delete them if they're empty or contain something like [].