discourse/app/assets/javascripts/admin/controllers/admin-site-content-edit.js.es6

import DiscourseController from 'discourse/controllers/controller';

export default DiscourseController.extend({

  saveDisabled: function() {
    if (this.get('saving')) { return true; }
    if ((!this.get('content.allow_blank')) && this.blank('content.content')) { return true; }
    return false;
  }.property('saving', 'content.content'),

  actions: {
    saveChanges: function() {
      var self = this;
      self.setProperties({saving: true, saved: false});
      self.get('content').save().then(function () {
        self.setProperties({saving: false, saved: true});
      });
    }
  }
});