4. Locastic
• We help clients create amazing web and mobile apps (since 2011)
• mobile development
• web development
• UX/UI
• Training and Consulting
• Shift Conference, Symfony Croatia
• www.locastic.com t: @locastic
15. “I don't care how many kick-ass Visio architecture diagrams
you have; as far as the user is concerned, the UI is the
application. I know UI US HARD, but you have to build an
impressive UI if you want to be taken seriously. Give your UI
the high priority it deserves.”
Jeff Atwood, Coding Horror blog
18. “A Progressive Web App uses
modern web capabilities to deliver
an app-like user experience.”
19. “A Progressive Web App uses
modern web capabilities to deliver
an app-like user experience.”
20. PWA is:
• Progressive - Works for every user, regardless of browser choice because it's
built with progressive enhancement as a core tenet.
• Responsive - Fits any form factor: desktop, mobile, tablet, or whatever is next.
• Connectivity independent - Enhanced with service workers to work offline or
on low-quality networks.
• App-like - Feels like an app, because the app shell model separates the
application functionality from application content .
• Fresh - Always up-to-date thanks to the service worker update process.
21. PWA is:
• Safe - Served via HTTPS to prevent snooping and to ensure content hasn't been
tampered with.
• Discoverable - Is identifiable as an "application" thanks to W3C manifest and
service worker registration scope, allowing search engines to find it.
• Re-engageable - Makes re-engagement easy through features like push
notifications.
• Installable - Allows users to add apps they find most useful to their home
screen without the hassle of an app store.
• Linkable - Easily share the application via URL, does not require complex
installation.
31. Integrated
• User should not reach browser to reach your app
• They should be able to interact same as with any other
app on their device
• They expect to have all possibilities as other apps
• Users should be able to start app from their home
screen
39. Broken experience
• Required user interaction
• Where it will start?
• Would it work offline?
https://medium.com/@saigeleslie/how-to-create-a-progressive-web-app-with-react-in-5-mins-or-less-3aae3fe98902
40. Web manifest
• Simple JSON file
• Tell browsers about your app and how it should behave once
app is ‘installed’
• Having manifest is required to show add to home screen pop-up
• Works for desktop and mobile apps (chrome)
• https://manifest-validator.appspot.com/
• https://app-manifest.firebaseapp.com/
44. What are the criteria?
• The web app is not already installed
• Meets a user engagement heuristic (currently, the user
has interacted with the domain for at least 30 seconds)
• Served over HTTPS (required for service workers)
• Has registered a service worker with a fetch event
handler
45. What are the criteria?
• Includes a web app manifest that includes:
• Short name or name
• Icons must include a 192px and a 512px sized icons
• start_url
• Display must be: fullscreen, standalone, or minimal-
ui
46. What are the criteria?
• When these criteria are met, Chrome will fire a
beforeinstallprompt event that you can use to
prompt the user to install your Progressive Web App.
let deferredPrompt;
window.addEventListener('beforeinstallprompt', (e) => {
// Prevent Chrome 67 and earlier from automatically showing the prompt
e.preventDefault();
// Stash the event so it can be triggered later.
deferredPrompt = e;
});
47. What are the criteria?
btnAdd.addEventListener('click', (e) => {
// hide our user interface that shows our A2HS button
btnAdd.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;
});
});
71. Reliable
• The quality of a network connection can be affected by a number of factors such as:
• Poor coverage of a provider.
• Extreme weather conditions.
• Power outages.
• Users travelling into “dead zones” such as buildings that block their network
connections.
• Travelling on a train and going through a tunnel.
• Internet connection is managed by a third party and time boxed when it will be
active or inactive like in an airport or hotel.
• Cultural practises that require limited or no internet access at specific times or days.
72. Reliable
• We need instant loading offline
• 60% of mobile connection is 2G
• Fast Application is UX
• 14 sec to load average website on 4g
• 19 sec to load average website on 3G
77. Service Workers
• Script that browser runs in background, separated
from web page
• It is Javascript worker, so it cannot access to DOM
directly
• Service worker is a programmable network proxy,
allowing you to control how network requests from
your page are handled.
78. Service Workers
• It's terminated when not in use, and restarted when
it's next needed, so you cannot rely on global state
within a service worker's onfetch and onmessage
handlers.
• Service workers make extensive use of promises
• Service worker is for second load
84. Cache and return requests
self.addEventListener('fetch', function(event) {
event.respondWith(
caches.match(event.request)
.then(function(response) {
// Cache hit - return response
if (response) {
return response;
}
return fetch(event.request);
}
)
);
});
85.
86. Service workers Events
• On install - as a dependency
• On install - not as a dependency
• On activate
• On user interaction
• On network response
• Stale-while-revalidate
• On push message
• On background-sync
87. Update Service Worker
• Update your service worker JavaScript file. When the user navigates to your
site, the browser tries to redownload the script file that defined the service
worker in the background. If there is even a byte's difference in the service
worker file compared to what it currently has, it considers it new.
• Your new service worker will be started and the install event will be fired.
• At this point the old service worker is still controlling the current pages so the
new service worker will enter a waiting state.
• When the currently open pages of your site are closed, the old service worker
will be killed and the new service worker will take control.
• Once your new service worker takes control, its activate event will be fired.
88. Update Service Worker
• self.skipWaiting()
• Skips waiting for refresh to start using new SW
90. // on user interaction
document.querySelector('.cache-article').addEventListener('click',
function(event) {
event.preventDefault();
var id = this.dataset.articleId;
caches.open('mysite-article-' + id).then(function(cache) {
fetch('/get-article-urls?id=' + id).then(function(response) {
// /get-article-urls returns a JSON-encoded array of
// resource URLs that a given article depends on
return response.json();
}).then(function(urls) {
cache.addAll(urls);
});
});
});
110. Reliable conclusion
• Think how you design for the success, failure and instability of a
network connection
• Data may be expensive, so be considerate to the user
• Make sure performance is part of your design process and UX
• Try to provide offline by default if your app doesn't require much
data
• Inform users of their current state and of changes in states
• https://serviceworke.rs/ - different examples
111. Your goal is to provide a good
experience that lessens the
impact of changes in
connectivity
113. Engaging
• Charming and Attractive
• Shift way how we think in patterns and designs from
web patterns to some native patterns
• Push notifications (browser doesn’t need to be
opened)
• Push Notification API
121. self.addEventListener('push', function(event) {
if (event.data.text() == 'new-email') {
event.waitUntil(
caches.open('mysite-dynamic').then(function(cache) {
return fetch('/inbox.json').then(function(response) {
cache.put('/inbox.json', response.clone());
return response.json();
});
}).then(function(emails) {
registration.showNotification("New email", {
body: "From " + emails[0].from.name
tag: "new-email"
});
})
);
}
});
self.addEventListener('notificationclick', function(event) {
if (event.notification.tag == 'new-email') {
// Assume that all of the resources needed to render
// /inbox/ have previously been cached, e.g. as part
// of the install handler.
new WindowClient('/inbox/');
}
});
122. Push Notifications
{
"body": "Did you make a $1,000,000 purchase at Dr. Evil...",
"icon": "images/ccard.png",
"vibrate": [200, 100, 200, 100, 200, 100, 400],
"tag": "request",
"actions": [
{ "action": "yes", "title": "Yes", "icon": "images/yes.png" },
{ "action": "no", "title": "No", "icon": "images/no.png" }
]
}
124. Credentials API!
• Removes friction from sign-in flows - Users can be
automatically signed back into a site even if their session has
expired or they saved credentials on another device.
• Allows one tap sign in with account chooser - Users can choose
an account in a native account chooser.
• Stores credentials - Your application can store either a
username and password combination or even federated account
details. These credentials can be synced across devices by the
browser.
135. Cut load times from 11.91 to 4.69
seconds
90% smaller than Native Android
App
https://medium.com/@addyosmani/a-tinder-progressive-web-app-performance-
case-study-78919d98ece0
Tinder
