Check for a text file (markdown) and check contents (if new), update the UI to show unread state, and then display a modal. Uses localStorage set to two items for unread and text content.

checkUpdateTextFile.js

        // uses https://github.com/markedjs/marked to read markdown files to html
        // uses jQuery because we're on old angular version

        var checkUpdatesFile = function() {
          $.ajax({
            url: '/static/updates.md'
          }).done(function(data){
            var updateText = data;

            // check/store in localStorage for updated text from updates.md
            if (localStorage.getItem('appUpdates') !== updateText) {
              localStorage.setItem('appUpdates', updateText); // update text content

              // show unread pip
              localStorage.setItem('updatesRead', false); 
              $('.ac-usernav .icon.notify').addClass('hasunread');

              console.log('App has updates.');
            } else {
              console.log('App no new updates.');
            }
          });
        };

        checkUpdatesFile();

        $(element).on('click', function (e) {
          e.preventDefault();

          checkUpdatesFile();

          // read from localstorage entry
          $('#updateBody').html(marked(localStorage.getItem('appUpdates')));  
          $('#modal-appupdates').modal('show');

          // remove unread pip
          localStorage.setItem('updatesRead', true);
          $(this).removeClass('hasunread');
          
          console.log('Displaying updates');
        });