jQuery Validate not setting correct language

[DaniG2k]

I'm trying to validate a form with jQuery validate but it's doesn't seem to be returning error messages in the correct language.

In my Rails app, I have:

gem 'jquery-validation-rails'

application.js

//= require rails-ujs
//= require turbolinks
//= require jquery
//= require bootstrap-sprockets
//= require jquery.validate
//= require jquery.validate.localization/messages_it
//= require jquery.validate.localization/messages_ja
//= require_tree .

I call the validator with:

document.addEventListener 'turbolinks:load', ->
  $("#contact-form").validate
    submitHandler: (form) ->
      form.submit()

  $('#first_name').rules 'add',
    required: true,
    maxlength: 15

  $('#last_name').rules 'add',
    required: true,
    maxlength: 15

  $('#entry_email').rules 'add',
    required: true,
    maxlength: 60

  $('#phone-number').rules 'add',
    required: true,
    digits: true

I am seeing the error messages, but they appear in Japanese even if I switch the page locale to en or it.

The language that appears is basically the last one I set in my application.js file. So if I remove //= require jquery.validate.localization/messages_ja then I get error messages in Italian.

How can I get error messages on a per-locale basis?

Any help on fixing this would be much appreciated!

Thanks in advance

[petitkriket]

https://stackoverflow.com/questions/49150000/jquery-validate-not-setting-correct-language answer is here if someone needs it