In your javascript, inject the ‘jira/util/events’ module and bind to NEW_CONTENT_ADDED with the reason ‘pageLoaded’. That’s how I do it.
require([
'jira/util/events',
'jira/util/events/types',
'jira/util/events/reasons'
], function(Events, EventTypes, EventReasons) {
"use strict";
Events.bind(EventTypes.NEW_CONTENT_ADDED, function(e, jiraContext, reason) {
// Do your stuff here but check for the reason first to avoid being called too often
});