JavaScript code:

window.addEventListener("beforeinstallprompt", function(a) {
    if (window.location.href.includes("mobile-app")) a.preventDefault(), window.deferredPrompt = a;
    else {
        if ("undefined" !== typeof window.beforeInstallPrompted) return !1;
        a.prompt();
        a.userChoice.then(function(a) {
            window.beforeInstallPrompted = !0;
            window.dataLayer.push({
                event: "homescreen.request"
            })
        })
    }
});
window.addEventListener("appinstalled", function() {
    window.dataLayer.push({
        event: "homescreen.install"
    })
});
(window.matchMedia("(display-mode: standalone)").matches || !0 === window.navigator.standalone) && ga("set", "dimension1");