pwa()

nebula.pwa()

nebula.pwa = function(){
    let installPromptEvent; //Scope it to this level

    //Listen for ability to show SW install prompt
    window.addEventListener('beforeinstallprompt', function(event){
        event.preventDefault(); //Prevent Chrome <= 67 from automatically showing the prompt
        installPromptEvent = event; //Stash the event so it can be triggered later.
        jQuery('.nebula-sw-install-button').removeClass('inactive').addClass('ready'); //Show the Nebula install button if it is present.
    });

    //Trigger the SW install prompt and handle user choice
    nebula.dom.document.on('click', '.nebula-sw-install-button', function(){
        if ( typeof installPromptEvent !== 'undefined' ){ //If the install event has been stashed for manual trigger
            jQuery('.nebula-sw-install-button').removeClass('ready').addClass('prompted');

            installPromptEvent.prompt(); //Show the modal add to home screen dialog

            let thisEvent = {
                event_name: 'pwa_install',
                event_category: 'Progressive Web App',
                event_action: 'Install Prompt Shown',
                event_label: 'The PWA install prompt was shown to the user',
            };

            nebula.dom.document.trigger('nebula_event', thisEvent);
            gtag('event', thisEvent.event_name, nebula.gaEventObject(thisEvent));

            //Wait for the user to respond to the prompt
            installPromptEvent.userChoice.then(function(result){
                jQuery('.nebula-sw-install-button').removeClass('prompted').addClass('ready');

                let thisEvent = {
                    event_name: 'pwa_install',
                    event_category: 'Progressive Web App',
                    event_action: 'Install Prompt User Choice',
                    result: result,
                    outcome: result.outcome,
                };

                nebula.dom.document.trigger('nebula_event', thisEvent);
                gtag('event', thisEvent.event_name, nebula.gaEventObject(thisEvent));
                nebula.crm('event', 'Install Prompt ' + thisEvent.outcome);
            });
        } else {
            jQuery('.nebula-sw-install-button').removeClass('ready').addClass('inactive');
        }

        return false;
    });

    //PWA installed to the device
    window.addEventListener('appinstalled', function(){
        jQuery('.nebula-sw-install-button').removeClass('ready').addClass('success');

        let thisEvent = {
            event_name: 'pwa_install',
            event_category: 'Progressive Web App',
            event_action: 'App Installed',
            event_label: 'The PWA has been installed',
        };

        nebula.dom.document.trigger('nebula_event', thisEvent);
        gtag('event', thisEvent.event_name, nebula.gaEventObject(thisEvent));
    });
};

For non-module import functions:

nebula.pwa = function(){
    //Write your own code here, leave it blank, or return false.
}

For dynamically imported module function overrides:

jQuery(window).on('load', function(){
    nebula.pwa = function(){
        //Write your own code here, leave it blank, or return false.
    }
});

Custom Nebula DOM events do also exist, so you could also try the following if the Window Load listener does not work:

jQuery(document).on('nebula_module_loaded', function(module){
    //Note that the module variable is also available to know which module specifically was imported
    if ( typeof nebula.pwa === 'function' ){
        nebula.pwa = function(){
            //Write your own code here, leave it blank, or return false.
        }
	}
});