Progressive Web Apps – the return of the web?

Chris Heilmann @codepo8, Goto Berlin, November 2016

Chris Heilmann @codepo8

There is a very cool thing happening right now…😃

💾The honeymoon period of native apps is over.🗑

🔥

💾🗑🔥

💾🗑🔥

💾🗑🔥

🌍However, there is still the problem of a changing world.

🖥→💻→📱Evolution is happening around us…

…and user numbers are shifting.

💔 The web wasn’t ready for the mobile form factor.

😠🌧Mobile was a throwback to the

web of old 🌧 Small screens, bad connectivity,

unreliable browser support 🌧 Constantly changing conditions 🌧 Hardwired browser and hardware

with unpredictable upgrades

⚠ We weren’t ready to go all out on web with mobile.

💾🌧 Instead of creating web sites that

work well on mobile, we packaged them up and submitted them to market places.

🌧 In a 1:1 comparison with native apps, they looked rubbish.

🍎 This may or may not have been by design

https://remysharp.com/2016/05/28/state-of-the-gap

These days, we’re looking much better…

The big breakthrough: Service Worker

https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API

🔧

Progressive Web Apps🦄

“Websites that have taken all the right vitamins”

– Alex Russel?

https://webmasters.googleblog.com/2016/11/building-indexable-progressive-web-apps.html

🦄🔧Work offline using Service Worker 🔧 Can hibernate and notify on

change 🔧 Possible progressive enhancement

of a working, standard web site 🔧More functionality with

subsequent visits 🔧 The link is the distribution model

🦄🔧 All the benefits of native apps -

none of the sluggish distribution issues

🔧Natural evolution of web content into the mobile form factor

🔧 A big opportunity to crack the closed distribution model

💷

Computers and smartphones are powerful. Browsers can do a lot and are open to feedback. JavaScript is flexible and has evolved. CSS has become amazing. Developer tools in browsers give us great debugging and even design capabilities

😍

🦄

🎉

💩 And yet, the mobile web is in a very sorry state.

🤔But, but but, everybody says the mobile web doesn’t exist! It’s just the web and we make it responsive…

🔬 Alright, let’s look at the problem…

This used to be much easier…

HTML (Structure)

CSS (Look and Feel)

JavaScript (Behaviour)

Flexibility and forgiveness…

💧 HTML and CSS are fault tolerant…

Knives, bees and footguns…

🦂 JavaScript is not fault tolerant

This is why we keep banging on about progressive enhancement

Using this, we can support the past…

And we can support current edge cases…

And after some checking, all the current browsers and what they support…

With HTML and CSS you’re relying on the user agent to do the right thing…😐

The HTML5 revolution promised a move from documents to apps…

The problem is that eight years after the proposal and five years after HTML5’s “last call”, there are still many basic support issues…

😦

https://vimeo.com/176453149

Monica Dinculescu < INPUT > HTML Special, CSS Day

https://www.filamentgroup.com/lab/type-number.html

And the bad people of the internet don’t stop abusing old technology either…💀

In UGC, we can’t have nice things…

https://mathiasbynens.github.io/rel-noopener/https://medium.com/@jitbit/target-blank-the-most-underestimated-vulnerability-ever-96e328301f4c#.mjuw7q3cf

Keep users on this page…

https://mathiasbynens.github.io/rel-noopener/https://medium.com/@jitbit/target-blank-the-most-underestimated-vulnerability-ever-96e328301f4c#.mjuw7q3cf

🔓💩

Fix for newer browsers…

https://mathiasbynens.github.io/rel-noopener/https://medium.com/@jitbit/target-blank-the-most-underestimated-vulnerability-ever-96e328301f4c#.mjuw7q3cf

Fix for all browsers…

https://mathiasbynens.github.io/rel-noopener/https://medium.com/@jitbit/target-blank-the-most-underestimated-vulnerability-ever-96e328301f4c#.mjuw7q3cf

Almost…

Listen for the click event and prevent the default browser behavior of opening a new tab. Inject a hidden iframe that opens the new tab, then immediately remove the iframe. “

https://github.com/danielstjules/blankshield

JavaScript isn’t evil.

Using JavaScript, you have a means to test if what you’re trying to do succeeded…✅

Supporting the past balancing act…

Use powerful language

additions…

Don’t block out older browsers and

environments…

Progressive enhancement balancing act

Control the UX with JavaScript and own

the failure cases.

Rely on the browser to give a “working”

experience.

I don’t have all the answers for you. A lot of this depends on your project, goals and resources.😳

!

JavaScript can’t be trusted and can be turned off.

💣 🔨Everybody has JavaScript, and we can do everything with it!

The “JavaScript not available” argument is largely bogus and is holding back the web!

⬇ 🎤

The “JavaScript is flaky and will break” argument is very much alive and will always be that way…🚧

Until the first successful load, you have no JavaScript functionality. That is a fact.B

However, subsequently, you can do a lot with JavaScript that is needed on mobile and can’t be done in HTML/CSS.

😊

New error cases become much more important than “JavaScript is not available”⚠

✏ Small initial payload ✏ Form factor supporting content ✏ Form factor supporting interfaces ✏ Offline/Flaky connection support ✏ Taking advantage of the power of

the end user device ✏ Avoiding interaction latency

❤📲

The beauty of HTML, CSS and JS…

😍 All is contained in one package 😍 Everything is running on the end users

environments 😍 You wouldn’t even need ServiceWorker to

make things work offline - inlining everything or using local storage would be enough

📦

Our solutions should have excellent error handling instead of automatic tolerance.👌

What about accessibility, eh?♿

Used sensibly, JavaScript is an accessibility boost. Sometimes the only way to make things accessible. ARIA is not magic.

🕹

https://codepo8.github.io/gridnav/

It is time we took ownership and responsibility of the whole technology stack.🔋

There is a culture of “let’s use whatever if it works”😐

We have a lot of messy solutions, and we keep building more tools to undo what clogs up the web.

Best practices can help with that, but only when they apply to the people who build things and when they solve current issues and needs…

Using instead of a URL or using a button is not JavaScript’s fault. It is a bad idea and practice - probably copy & paste.

💩<a href="javascript:void(0)">

Instead of bashing bad use of JavaScript, let’s embrace and scrutinise new ideas.🔎

🆙🔧 Any web product can become a

Progressive Web App, not all have to be.

🔧 You’ll reap the rewards of simple maintenance and upgrade paths and the form factor mobile users expect.

🔧 However, it makes sense to clean up before going there…

🛠

🔧 Look at what you built, check the current state of affairs at http://caniuse.com and remove all the cruft you don’t need.

🔧 Simplify your interfaces, the next users are impatient and on flaky connections.

🔧 Reconsider the ways you build and deploy your products, a lot can be automated.

✅ Create and publish as much content independent of JavaScript as you can

✅ JavaScript can make things much more enjoyable and some things are just not worth while to implement without.

✅ Benefit from the user’s hardware ✅ Spend more time building great

interfaces, less time relying on what is there and can’t break - in many cases it is disappointing.

It is time to re-think our best practice for the web approach…

🙂 You don’t rely on automatic fixes. JavaScript breaks and it is painful. It allows us to analyse what went wrong.

🙂 Tooling is much better and we get much more insights into what happened than with, for example, CSS

🙂 We take responsibility of the interface. It is our job to make it happen - not browser makers to agree and find a consensus

🙂 We have full control over what gets loaded when, cached where and rendered when.

Benefits of an “It’s OK to rely on JS for this” approach…

⚠ We shouldn’t hide functionality in magical abstractions. A product that relies on the availability and maintenance of a framework is not a script dependency - it is a support issue.

⚠ Just because we can do everything in JavaScript, doesn’t mean we have to. Use it when HTML is not good enough or too broken to rely on.

⚠ While the client is powerful, it is also unknown. A lot more can be done on the server - and in JavaScript.

Dangers to be aware of…

Important considerations independent of technology used…

💣 Shit happens! Spend more time in creating sensible error messaging and fallbacks, spend less time in trying to predict every possible error

💣 Slowness kills - our solutions must load fast what is needed and enhance when they can. They also need to be snappy.

💣 Offline and flaky is the norm - avoid network dependency as much as you can

💣 Security is paramount. A hacked server sending out malware or spam is worse than an app that needs a restart…

We have to stop thinking in binaries, and consider writing great, secure and failure-aware solutions using each technology to its strengths.

🐝

CHRIS HEILMANN

@CODEPO8

CHRISTIANHEILMANN.COM

THANKS!