BeforeInstallPromptEvent - Web APIs
beforeinstallpromptevent.userchoice read only returns a promise that resolves to a domstring containing either "accepted" or "dismissed".
... example window.addeventlistener("beforeinstallprompt", function(e) { // log the platforms provided as options in an install prompt console.log(e.platforms); // e.g., ["web", "android", "windows"] e.userchoice.then(function(choiceresult) { console.log(choiceresult.outcome); // either "accepted" or "dismissed" }, handleerror); }); ...

Add to Home screen - Progressive web apps (PWAs)
deferredprompt = e; // update ui to notify the user they can add to home screen addbtn.style.display = 'block'; addbtn.addeventlistener('click', (e) => { // hide our user interface that shows our a2hs button addbtn.style.display = 'none'; // show the prompt deferredprompt.prompt(); // wait for the user to respond to the prompt deferredprompt.userchoice.then((choiceresult) => { if (choiceresult.outcome === 'accepted') { console.log('user accepted the a2hs prompt'); } else { console.log('user dismissed the a2hs prompt'); } deferredprompt = null; }); }); }); so here we: call event.preventdefault() to stop chrome 67 and earlier from calling the install prompt automatically (this behavi...
... respond to the user's interaction with the prompt using the userchoice property, again available on the beforeinstallprompt event object.