overleaf/services/web/frontend/js/main/translations.js

import App from '../base'

App.controller(
  'TranslationsPopupController',
  function ($scope, ipCookie, localStorage) {
    function getStoredDismissal() {
      let localStore = localStorage('hide-i18n-notification')

      if (localStore === null) {
        // Not stored in localStorage, check cookie
        let cookieStore = ipCookie('hidei18nNotification')

        // If stored in cookie, set on localStorage for forwards compat
        if (cookieStore) {
          localStorage('hide-i18n-notification', cookieStore)
          ipCookie.remove('hidei18nNotification')
        }

        return cookieStore
      }

      return localStore
    }

    $scope.hidei18nNotification = getStoredDismissal()

    $scope.dismiss = function () {
      localStorage('hide-i18n-notification', true)
      $scope.hidei18nNotification = true
    }
  }
)