“A Progressive Web App uses modern web capabilities to deliver an
app-like user experience.”

Google, 2015

You already use PWA

 Reliable:      must load instantly
                        regardless of network connectivity
 

 Fast:              navigation and interactions are fluid

                        no lag, no stagger while scrolling
 

Attractive:    fits naturally in user system

                         immersive and consistent user experience

3 main objectives
for a PWA

Web technologies are inherently backward compatible.

If a feature is not supported, the app remains functional.

This is called Progressive Enhancement

Why "Progressive" ?

Illustration by Tiffany Tse

Network resilience
Beyond online / offline

Internet connectivity is ephemeral and misleading,

especially on mobile.

Challenges and technical constraints highly depend on the context
(eg use in a train or a plane)

Network handling strategies

Common caching strategies:

• Precaching
• Cache as fallback
• Respond with cache, update in parallel        

Common error handling strategies:

• User-controlled recovery
• Auto-recovery with progressive delay
• Ordered stack of failed requests
• Real-time apps and operational transforms

Optimistic UI

Latency compensation

With full client-side JS frameworks, we don't have
to wait for the server response to refresh the view.

= huge perceived performance gain

+ needs a good error management strategy

PWA and Frameworks

"Out of the box" PWA
in all popular JS frameworks

Typical PWA Architecture

What Web can do today

Native vs web debate, once again

Debate #1:
Have PWA changed the game ?

Debate #2:
Did PWA kill server pages ?

Debate #3:
Will PWA sell web tech
for desktop apps ?

Notre topic PWA dans la

Un support complet de documentation accessible à tous:
            pwa-cookbook.js.org
 

Un workshop pour vous former rapidement:
            pwa-workshop.js.org

Des présentations pour sensibiliser aux PWA
 

Du support personnalisé pour répondre à vos questions