Tags: java

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Thursday, September 24th, 2020

Performance and people

I was helping a client with a bit of a performance audit this week. I really, really enjoy this work. It’s such a nice opportunity to get my hands in the soil of a website, so to speak, and suggest changes that will have a measurable effect on the user’s experience.

Not only is web performance a user experience issue, it may well be the user experience issue. Page speed has a proven demonstrable direct effect on user experience (and revenue and customer satisfaction and whatever other metrics you’re using).

It struck me that there’s a continuum of performance challenges. On one end of the continuum, you’ve got technical issues. These can be solved with technical solutions. On the other end of the continuum, you’ve got human issues. These can be solved with discussions, agreement, empathy, and conversations (often dreaded or awkward).

I think that, as developers, we tend to gravitate towards the technical issues. That’s our safe space. But I suspect that bigger gains can be reaped by tackling the uncomfortable human issues.

This week, for example, I uncovered three performance issues. One was definitely technical. One was definitely human. One was halfway between.

The technical issue was with web fonts. It’s a lot of fun to dive into this aspect of web performance because quite often there’s some low-hanging fruit: a relatively simple technical fix that will boost the performance (or perceived performance) of a website. That might be through resource hints (using link rel=“preload” in the HTML) or adjusting the font loading (using font-display in the CSS) or even nerdier stuff like subsetting.

In this case, the issue was with the file format of the font itself. By switching to woff2, there were significant file size savings. And the great thing is that @font-face rules allow you to specify multiple file formats so you can still support older browsers that can’t handle woff2. A win all ‘round!

The performance issue that was right in the middle of the technical/human continuum was with images. At first glance it looked like a similar issue to the fonts. Some images were being served in the wrong formats. When I say “wrong”, I guess I mean inappropriate. A photographic image, for example, is probably going to best served as a JPG rather than a PNG.

But unlike the fonts, the images weren’t in the direct control of the developers. These images were coming from a Content Management System. And while there’s a certain amount of processing you can do on the server, a human still makes the decision about what file format they’re uploading.

I’ve seen this happen at Clearleft. We launched an event site with lean performant code, but then someone uploaded an image that’s megabytes in size. The solution in that case wasn’t technical. We realised there was a knowledge gap around image file formats—which, let’s face it, is kind of a techy topic that most normal people shouldn’t be expected to know.

But it was extremely gratifying to see that people were genuinely interested in knowing a bit more about choosing the right format for the right image. I was able to provide a few rules of thumb and point to free software for converting images. It empowered those people to feel more confident using the Content Management System.

It was a similar situation with the client site I was looking at this week. Nobody is uploading oversized images in order to deliberately make the site slower. They probably don’t realise the difference that image formats can make. By having a discussion and giving them some pointers, they’ll have more knowledge and the site will be faster. Another win all ‘round!

At the other end of continuum was an issue that wasn’t technical. From a technical point of view, there was just one teeny weeny little script. But that little script is Google Tag Manager which then calls many, many other scripts that are not so teeny weeny. Third party scripts …the bane of web performance!

In retrospect, it seems unbelievable that third-party JavaScript is even possible. I mean, putting arbitrary code—that can then inject even more arbitrary code—onto your website? That seems like a security nightmare!

Remember when I did a countdown of the top four web performance challenges? At the number one spot is other people’s JavaScript.

Now one technical solution would be to remove the Google Tag Manager script. But that’s probably not very practical—you’ll probably just piss off some other department. That said, if you can’t find out which department was responsible for adding the Google Tag Manager script in the first place, it might we well be an option to remove it and then wait and see who complains. If no one notices it’s gone, job done!

More realistically, there’s someone who’s added that Google Tag Manager script for their own valid reasons. You’ll need to talk to them and understand their needs.

Again, as with images uploaded in a Content Management System, they may not be aware of the performance problems caused by third-party scripts. You could try throwing numbers at them, but I think you get better results by telling the story of performance.

Use tools like Request Map Generator to help them visualise the impact that third-party scripts are having. Talk to them. More importantly, listen to them. Find out why those scripts are being requested. What are the outcomes they’re working towards? Can you offer an alternative way of providing the data they need?

I think many of us developers are intimidated or apprehensive about approaching people to have those conversations. But it’s necessary. And in its own way, it can be as rewarding as tinkering with code. If the end result is a faster website, then the work is definitely worth doing—whether it’s technical work or people work.

Personally, I just really enjoy working on anything that will end up improving a website’s performance, and by extension, the user experience. If you fancy working with me on your site, you should get in touch with Clearleft.

The failed promise of Web Components – Lea Verou

A spot-on summary of where we’ve ended up with web components.

Web Components had so much potential to empower HTML to do more, and make web development more accessible to non-programmers and easier for programmers.

But then…

Somewhere along the way, the space got flooded by JS frameworks aficionados, who revel in complex APIs, overengineered build processes and dependency graphs that look like the roots of a banyan tree.

Alas, that’s true. Lea wonders how this can be fixed:

I’m not sure if this is a design issue, or a documentation issue.

I worry that is a cultural issue.

Using a custom element from the directory often needs to be preceded by a ritual of npm flugelhorn, import clownshoes, build quux, all completely unapologetically because “here is my truckload of dependencies, yeah, what”.

Tuesday, September 22nd, 2020

The Economics of the Front-End - Jim Nielsen’s Weblog

I do think large tech companies employ JavaScript frameworks because, amongst other things, it saves them money at their scale. And what Big Tech does trickles down in the form of default choices for many others (“they’re doing it and are insanely successful, so mimicking them can’t be a bad idea”). However, the scale at which smaller projects operate doesn’t necessarily translate to the same kind of cost savings.

Monday, September 21st, 2020

The web we left behind by Kyle Jacobson (ESNEXT 2020) - YouTube

This is such an excellent presentation! It really resonates with me.

Kyle Jacobson is a developer who’s been working with the web for over 10 years, and he talks about lessons from the past that can make the future of the web not only easier to develop using battle-tested technologies, but also one friendlier for humans.

The web we left behind by Kyle Jacobson (ESNEXT 2020)

Wednesday, September 16th, 2020

A polyfill for button type=”share”

After writing about a declarative Web Share API here yesterday I thought I’d better share the idea (see what I did there?).

I opened an issue on the Github repo for the spec.

(I hope that’s the right place for this proposal. I know that in the past ideas were kicked around on the Discourse site for Web platform Incubator Community Group but I can’t stand Discourse. It literally requires JavaScript to render anything to the screen even though the entire content is text. If it turns out that that is the place I should’ve posted, I guess I’ll hold my nose and do it using the most over-engineered reinvention of the browser I’ve ever seen. But I believe that the plan is for WICG to migrate proposals to Github anyway.)

I also realised that, as the JavaScript Web Share API already exists, I can use it to polyfill my suggestion for:

<button type="share">

The polyfill also demonstrates how feature detection could work. Here’s the code.

This polyfill takes an Inception approach to feature detection. There are three nested levels:

  1. This browser supports button type="share". Great! Don’t do anything. Otherwise proceed to level two.
  2. This browser supports the JavaScript Web Share API. Use that API to share the current page URL and title. Otherwise proceed to level three.
  3. Use a mailto: link to prefill an email with the page title as the subject and the URL in the body. Ya basic!

The idea is that, as long as you include the 20 lines of polyfill code, you could start using button type="share" in your pages today.

I’ve made a test page on Codepen. I’m just using plain text in the button but you could use a nice image or SVG or combination. You can use the Codepen test page to observe two of the three possible behaviours browsers could exhibit:

  1. A browser supports button type="share". Currently that’s none because I literally made this shit up yesterday.
  2. A browser supports the JavaScript Web Share API. This is Safari on Mac, Edge on Windows, Safari on iOS, and Chrome, Samsung Internet, and Firefox on Android.
  3. A browser supports neither button type="share" nor the existing JavaScript Web Share API. This is Firefox and Chrome on desktop (and Edge if you’re on a Mac).

See the Pen Polyfill for button type=”share" by Jeremy Keith (@adactio) on CodePen.

The polyfill doesn’t support Internet Explorer 11 or lower because it uses the DOM closest() method. Feel free to fork and rewrite if you need to support old IE.

Tuesday, September 15th, 2020

A declarative Web Share API

I’ve written about the Web Share API before. It’s a handy little bit of JavaScript that—if supported—brings up a system-level way of sharing a page. Seeing as it probably won’t be long before we won’t be able to see full URLs in browsers anymore, it’s going to fall on us as site owners to provide this kind of fundamental access.

Right now the Web Share API exists entirely in JavaScript. There are quite a few browser APIs like that, and it always feels like a bit of a shame to me. Ideally there should be a JavaScript API and a declarative option, even if the declarative option isn’t as powerful.

Take form validation. To cover the most common use cases, you probably only need to use declarative markup like input type="email" or the required attribute. But if your use case gets a bit more complicated, you can reach for the Constraint Validation API in JavaScript.

I like that pattern. I wish it were an option for JavaScript-only APIs. Take the Geolocation API, for example. Right now it’s only available through JavaScript. But what if there were an input type="geolocation" ? It wouldn’t cover all use cases, but it wouldn’t have to. For the simple case of getting someone’s location (like getting someone’s email or telephone number), it would do. For anything more complex than that, that’s what the JavaScript API is for.

I was reminded of this recently when Ada Rose Cannon tweeted:

It really feels like there should be a semantic version of the share API, like a mailto: link

I think she’s absolutely right. The Web Share API has one primary use case: let the user share the current page. If that use case could be met in a declarative way, then it would have a lower barrier to entry. And for anyone who needs to do something more complicated, that’s what the JavaScript API is for.

But Pete LePage asked:

How would you feature detect for it?

Good question. With the JavaScript API you can do feature detection—if the API isn’t supported you can either bail or provide your own implementation.

There a few different ways of extending HTML that allow you to provide a fallback for non-supporting browsers.

You could mint a new element with a content model that says “Browsers, if you do support this element, ignore everything inside the opening and closing tags.” That’s the way that the canvas element works. It’s the same for audio and video—they ignore everything inside them that isn’t a source element. So developers can provide a fallback within the opening and closing tags.

But forging a new element would be overkill for something like the Web Share API (or Geolocation). There are more subtle ways of extending HTML that I’ve already alluded to.

Making a new element is a lot of work. Making a new attribute could also be a lot of work. But making a new attribute value might hit the sweet spot. That’s why I suggested something like input type="geolocation" for the declarative version of the Geolocation API. There’s prior art here; this is how we got input types for email, url, tel, color, date, etc. The key piece of behaviour is that non-supporting browsers will treat any value they don’t understand as “text”.

I don’t think there should be input type="share". The action of sharing isn’t an input. But I do think we could find an existing HTML element with an attribute that currently accepts a list of possible values. Adding one more value to that list feels like an inexpensive move.

Here’s what I suggested:

<button type=”share” value=”title,text”>

For non-supporting browsers, it’s a regular button and needs polyfilling, no different to the situation with the JavaScript API. But if supported, no JS needed?

The type attribute of the button element currently accepts three possible values: “submit”, “reset”, or “button”. If you give it any other value, it will behave as though you gave it a type of “submit” or “button” (depending on whether it’s in a form or not) …just like an unknown type value on an input element will behave like “text”.

If a browser supports button type="share”, then when the user clicks on it, the browser can go “Right, I’m handing over to the operating system now.”

There’s still the question of how to pass data to the operating system on what gets shared. Currently the JavaScript API allows you to share any combination of URL, text, and description.

Initially I was thinking that the value attribute could be used to store this data in some kind of key/value pairing, but the more I think about it, the more I think that this aspect should remain the exclusive domain of the JavaScript API. The declarative version could grab the current URL and the value of the page’s title element and pass those along to the operating system. If you need anything more complex than that, use the JavaScript API.

So what I’m proposing is:

<button type="share">

That’s it.

But how would you test for browser support? The same way as you can currently test for supported input types. Make use of the fact that an element’s attribute value and an element’s property value (which 99% of the time are the same), will be different if the attribute value isn’t supported:

var testButton = document.createElement("button");
testButton.setAttribute("type","share");
if (testButton.type != "share") {
// polyfill
}

So that’s my modest proposal. Extend the list of possible values for the type attribute on the button element to include “share” (or something like that). In supporting browsers, it triggers a very bare-bones handover to the OS (the current URL and the current page title). In non-supporting browsers, it behaves like a button currently behaves.

Friday, August 28th, 2020

Why you should hire a frontend developer - Technology in government

This is a really good description of the role of a front-end developer.

That’s front end, not full stack.

Wednesday, August 26th, 2020

Submitting a form with datalist

I’m a big fan of HTML5’s datalist element and its elegant design. It’s a way to progressively enhance any input element into a combobox.

You use the list attribute on the input element to point to the ID of the associated datalist element.

<label for="homeworld">Your home planet</label>
<input type="text" name="homeworld" id="homeworld" list="planets">
<datalist id="planets">
 <option value="Mercury">
 <option value="Venus">
 <option value="Earth">
 <option value="Mars">
 <option value="Jupiter">
 <option value="Saturn">
 <option value="Uranus">
 <option value="Neptune">
</datalist>

It even works on input type="color", which is pretty cool!

The most common use case is as an autocomplete widget. That’s how I’m using it over on The Session, where the datalist is updated via Ajax every time the input is updated.

But let’s stick with a simple example, like the list of planets above. Suppose the user types “jup” …the datalist will show “Jupiter” as an option. The user can click on that option to automatically complete their input.

It would be handy if you could automatically submit the form when the user chooses a datalist option like this.

Well, tough luck.

The datalist element emits no events. There’s no way of telling if it has been clicked. This is something I’ve been trying to find a workaround for.

I got my hopes up when I read Amber’s excellent article about document.activeElement. But no, the focus stays on the input when the user clicks on an option in a datalist.

So if I can’t detect whether a datalist has been used, this best I can do is try to infer it. I know it’s not exactly the same thing, and it won’t be as reliable as true detection, but here’s my logic:

  • Keep track of the character count in the input element.
  • Every time the input is updated in any way, check the current character count against the last character count.
  • If the difference is greater than one, something interesting happened! Maybe the user pasted a value in …or maybe they used the datalist.
  • Loop through each of the options in the datalist.
  • If there’s an exact match with the current value of the input element, chances are the user chose that option from the datalist.
  • So submit the form!

Here’s how that translates into DOM scripting code:

document.querySelectorAll('input[list]').forEach( function (formfield) {
  var datalist = document.getElementById(formfield.getAttribute('list'));
  var lastlength = formfield.value.length;
  var checkInputValue = function (inputValue) {
    if (inputValue.length - lastlength > 1) {
      datalist.querySelectorAll('option').forEach( function (item) {
        if (item.value === inputValue) {
          formfield.form.submit();
        }
      });
    }
    lastlength = inputValue.length;
  };
  formfield.addEventListener('input', function () {
    checkInputValue(this.value);
  }, false);
});

I’ve made a gist with some added feature detection and mustard-cutting at the start. You should be able to drop it into just about any page that’s using datalist. It works even if the options in the datalist are dynamically updated, like the example on The Session.

It’s not foolproof. The inference relies on the difference between what was previously typed and what’s autocompleted to be more than one character. So in the planets example, if someone has type “Jupite” and then they choose “Jupiter” from the datalist, the form won’t automatically submit.

But still, I reckon it covers most common use cases. And like the datalist element itself, you can consider this functionality a progressive enhancement.

Thursday, August 20th, 2020

Service Workers | Go Make Things

Chris Ferdinandi blogs every day about the power of vanilla JavaScript. For over a week now, his daily posts have been about service workers. The cumulative result is this excellent collection of resources.

Wednesday, August 19th, 2020

Make Your Own Dev Tool | Amber’s Website

I love bookmarklets! I use them every day (I’m using one right now to post this link). Amber does a great job explaining what they are and how you can make one. I really like the way she frames them as your own personal dev tools!

radEventListener: a Tale of Client-side Framework Performance | CSS-Tricks

Excellent research by Jeremy Wagner comparing the performance impact of React, Preact, and vanilla JavaScript. The results are simultaneously shocking and entirely unsurprising.

Sunday, August 16th, 2020

Web Technologies and Syntax | Jim Nielsen’s Weblog

Syntactic sugar can’t help you if you don’t understand how things work under the hood. Optional chaining in JavaScript and !important in CSS are ways of solving your immediate problem …but unless you know what you’re doing, they’re probably going to create new problems.

Saturday, August 1st, 2020

this vs that - What is the difference between ___ and ___ in the front-end development?

A handy reference for explaining the differences between confusingly similar bits of HTML, CSS, and JavaScript.

Friday, July 31st, 2020

Smashing Podcast Episode 21 With Chris Ferdinandi: Are Modern Best Practices Bad For The Web? — Smashing Magazine

I really enjoyed this interview between Drew and Chris. I love that there’s a transcript so you can read the whole thing if you don’t feel like huffduffing it.

Friday, July 24th, 2020

Progressive · Matthias Ott – User Experience Designer

Progressive enhancement is not yet another technology or passing fad. It is a lasting strategy, a principle, to deal with complexity because it lets you build inclusive, resilient experiences that work across different contexts and that will continue to work, once the next fancy JavaScript framework enters the scene – and vanishes again.

But why don’t more people practice progressive enhancement? Is it only because they don’t know better? This might, in fact, be the primary reason. On top of that, especially many JavaScript developers seem to believe that it is not possible or necessary to build modern websites and applications that way.

A heartfelt look at progressive enhancement:

Some look at progressive enhancement like a thing from the past of which the old guard just can’t let go. But to me, progressive enhancement is the future of the Web. It is the basis for building resilient, performant, interoperable, secure, usable, accessible, and thus inclusive experiences. Not only for the Web of today but for the ever-growing complexity of an ever-changing and ever-evolving Web.

Saturday, July 18th, 2020

Indexing your offline-capable pages with the Content Indexing API

A Chrome-only API for adding offline content to an index that can be exposed in Android’s “downloads” list. It just shipped in the lastest version of Chrome.

I’m not a fan of browser-specific non-standards but you can treat this as an enhancement—implementing it doesn’t harm non-supporting browsers and you can use feature detection to test for it.

An Introduction To Stimulus.js — Smashing Magazine

An intro to Stimulus, the lightweight JavaScript library from Basecamp that takes a progressive enhancement approach, as seen with HEY.

One aspect I really like about the approach Stimulus encourages, is I can focus on sending HTML down the wire to my users, which is then jazzed up a little with JavaScript.

I’ve always been a fan of using the first few milliseconds of a user’s attention getting what I have to share with them — in front of them. Then worrying setting up the interaction layer while the user can start processing what they’re seeing.

Furthermore, if the JavaScript were to fail for whatever reason, the user can still see the content and interact with it without JavaScript.

Your blog doesn’t need a JavaScript framework /// Iain Bean

If the browser needs to parse 296kb of JavaScript to show a list of blog posts, that’s not Progressive Enhancement, it’s using the wrong tool for the job.

A good explanation of the hydration problem in tools like Gatsby.

JavaScript is a powerful language that can do some incredible things, but it’s incredibly easy to jump to using it too early in development, when you could be using HTML and CSS instead.

Thursday, July 16th, 2020

Hey now

Progressive enhancement is at the heart of everything I do on the web. It’s the bedrock of my speaking and writing too. Whether I’m writing about JavaScript, Ajax, HTML, or service workers, it’s always through the lens of progressive enhancement. Sometimes I explicitly bang the drum, like with Resilient Web Design. Other times I don’t mention it by name at all, and instead talk only about its benefits.

I sometimes get asked to name some examples of sites that still offer their core functionality even when JavaScript fails. I usually mention Amazon.com, although that has other issues. But quite often I find that a lot of the examples I might mention are dismissed as not being “web apps” (whatever that means).

The pushback I get usually takes the form of “Well, that approach is fine for websites, but it wouldn’t work something like Gmail.”

It’s always Gmail. Which is odd. Because if you really wanted to flummox me with a product or service that defies progressive enhancement, I’d have a hard time with something like, say, a game (although it would be pretty cool to build a text adventure that’s progressively enhanced into a first-person shooter). But an email client? That would work.

Identify core functionality.

Read emails. Write emails.

Make that functionality available using the simplest possible technology.

HTML for showing a list of emails, HTML for displaying the contents of the HTML, HTML for the form you write the response in.

Enhance!

Now add all the enhancements that improve the experience—keyboard shortcuts; Ajax instead of full-page refreshes; local storage, all that stuff.

Can you build something that works just like Gmail without using any JavaScript? No. But that’s not what progressive enhancement is about. It’s about providing the core functionality (reading and writing emails) with the simplest possible technology (HTML) and then enhancing using more powerful technologies (like JavaScript).

Progressive enhancement isn’t about making a choice between using simpler more robust technologies or using more advanced features; it’s about using simpler more robust technologies and then using more advanced features. Have your cake and eat it.

Fortunately I no longer need to run this thought experiment to imagine what it would be like if something like Gmail were built with a progressive enhancement approach. That’s what HEY is.

Sam Stephenson describes the approach they took:

HEY’s UI is 100% HTML over the wire. We render plain-old HTML pages on the server and send them to your browser encoded as text/html. No JSON APIs, no GraphQL, no React—just form submissions and links.

If you think that sounds like the web of 25 years ago, you’re right! Except the HEY front-end stack progressively enhances the “classic web” to work like the “2020 web,” with all the fidelity you’d expect from a well-built SPA.

See? It’s not either resilient or modern—it’s resilient and modern. Have your cake and eat it.

And yet this supremely sensible approach is not considered “modern” web development:

The architecture astronauts who, for the past decade, have been selling us on the necessity of React, Redux, and megabytes of JS, cannot comprehend the possibility of building an email app in 2020 with server-rendered HTML.

HEY isn’t perfect by any means—they’ve got a lot of work to do on their accessibility. But it’s good to have a nice short answer to the question “But what about something like Gmail?”

It reminds me of responsive web design:

When Ethan Marcotte demonstrated the power of responsive design, it was met with resistance. “Sure, a responsive design might work for a simple personal site but there’s no way it could scale to a large complex project.”

Then the Boston Globe launched its responsive site. Microsoft made their homepage responsive. The floodgates opened again.

It’s a similar story today. “Sure, progressive enhancement might work for a simple personal site, but there’s no way it could scale to a large complex project.”

The floodgates are ready to open. We just need you to create the poster child for resilient web design.

It looks like HEY might be that poster child.

I have to wonder if its coincidence or connected that this is a service that’s also tackling ethical issues like tracking? Their focus is very much on people above technology. They’ve taken a human-centric approach to their product and a human-centric approach to web development …because ultimately, that’s what progressive enhancement is.

Saturday, July 11th, 2020

A little bit of plain Javascript can do a lot

I decided to implement almost all of the UI by just adding & removing CSS classes, and using CSS transitions if I want to animate a transition.

Yup. It’s remarkable how much can be accomplished with that one DOM scripting pattern.

I was pretty surprised by how much I could get done with just plain JS. I ended up writing about 50 lines of JS to do everything I wanted to do.