Journal tags: simplicity

I received this email recently:

Subject: multi-page web apps

Hi Jeremy,

lately I’ve been following you through videos and texts and I’m curious as to why you advocate the use of multi-page web apps and not single-page ones.

Perhaps you can refer me to some sources where your position and reasoning is evident?

Here’s the response I sent…

Hi,

You can find a lot of my reasoning laid out in this (short and free) online book I wrote called Resilient Web Design:

https://resilientwebdesign.com/

The short answer to your question is this: user experience.

The slightly longer answer…

For most use cases, a website (or multi-page app if you prefer) is going to provide the most robust experience for the most number of users. That’s because a user’s web browser takes care of most of the heavy lifting.

Navigating from one page to another? That’s taken care of with links.

Gathering information from a user to process on a server? That’s taken care of with forms.

This frees me up to concentrate on the content and the design without having to reinvent the wheels of links and form fields.

These (let’s call them) multi-page apps are stateless, and for most use cases that’s absolutely fine.

There are some cases where you’d want a state to persist across pages. Let’s say you’re playing a song, or a podcast episode. Ideally you’d want that player to continue seamlessly playing even as the user navigates around the site. In that situation, a single-page app would be a suitable architecture.

But that architecture comes at a cost. Now you’ve got stop the browser doing what it would normally do with links and forms. It’s up to you to recreate that functionality. And you can’t do it with HTML, a robust fault-tolerant declarative language. You need to reimplement all that functionality in JavaScript, a less tolerant, more brittle language.

Then you’ve got to ship all that code to the user before they can use your site. It might be JavaScript code you’ve written yourself or it might be a third-party library designed for building single-page apps. Either way, the user pays a download tax (and a parsing tax, and an execution tax). Whereas with links and forms, all of that functionality is pre-bundled into the user’s web browser.

So that’s my reasoning. At least nine times out of ten, a multi-page approach is leaner, more robust, and simpler.

Like I said, there are times when a single-page approach makes sense—it all comes down to whether state needs to be constantly preserved. But these use cases are the exceptions, not the rule.

That’s why I find the framing of your question a little concerning. It should be inverted. The default approach should be to assume a multi-page approach (which is the way the web works by default). Deciding to take a JavaScript-driven single-page approach should be the exception.

It’s kind of like when people ask, “Why don’t you have children?” Surely the decision to have a child should require deliberation and commitment, rather than the other way around.

When it comes to front-end development, I’m worried that we’ve reached a state where the more complex over-engineered approach is viewed as the default.

I may be committing a fundamental attribution error here, but I think that we’ve reached this point not because of any consideration for users, but rather because of how it makes us developers feel. Perhaps building an old-fashioned website that uses HTML for navigations feels too easy, like it’s beneath us. But building an “app” that requires JavaScript just to render text on a screen feels like real programming.

I hope I’m wrong. I hope that other developers will start to consider user experience first and foremost when making architectural decisions.

Anyway. That’s my answer. User experience.

Cheers,

Jeremy

I work with words. Sometimes they’re my words. Sometimes they’re words that my colleagues have written:

One of my roles at Clearleft is “content buddy.” If anyone is writing a talk, or a blog post, or a proposal and they want an extra pair of eyes on it, I’m there to help.

I also work with web technologies, usually front-of-the-front-end stuff. HTML, CSS, and JavaScript. The technologies that users experience directly in web browsers.

I think a lot about design principles for the web. The two principles I keep coming back to are the robustness principle and the principle of least power.

When it comes to words, the guide that I return to again and again is George Orwell, specifically his short essay, Politics and the English Language.

Towards the end, he offers some rules for writing.

1. Never use a metaphor, simile, or other figure of speech which you are used to seeing in print.
2. Never use a long word where a short one will do.
3. If it is possible to cut a word out, always cut it out.
4. Never use the passive where you can use the active.
5. Never use a foreign phrase, a scientific word, or a jargon word if you can think of an everyday English equivalent.
6. Break any of these rules sooner than say anything outright barbarous.

These look a lot like design principles. Not only that, but some of them look like specific design principles. Take the robustness principle:

Be conservative in what you send, be liberal in what you accept.

That first part applies to Orwell’s third rule:

If it is possible to cut a word out, always cut it out.

Be conservative in what words you send.

Then there’s the principle of least power:

Choose the least powerful language suitable for a given purpose.

Compare that to Orwell’s second rule:

Never use a long word where a short one will do.

That could be rephrased as:

Choose the shortest word suitable for a given purpose.

Or, going in the other direction, the principle of least power could be rephrased in Orwell’s terms as:

Never use a powerful language where a simple language will do.

Oh, I like that! I like that a lot.

There’s a great article by Steven Garrity over on A List Apart called Design with Difficult Data. It runs through the advantages of using unusual content to stress-test interfaces, referencing Postel’s Law, AKA the robustness principle:

Be conservative in what you send, be liberal in what you accept.

Even though the robustness principle was formulated for packet-switching, I see it at work in all sorts of disciplines, including design. A good example is in best practices for designing forms:

Every field you ask users to fill out requires some effort. The more effort is needed to fill out a form, the less likely users will complete the form. That’s why the foundational rule of form design is shorter is better — get rid of all inessential fields.

In other words, be conservative in the number of form fields you send to users. But then, when it comes to users filling in those fields:

It’s very common for a few variations of an answer to a question to be possible; for example, when a form asks users to provide information about their state, and a user responds by typing their state’s abbreviation instead of the full name (for example, CA instead of California). The form should accept both formats, and it’s the developer job to convert the data into a consistent format.

In other words, be liberal in what you accept from users.

I find the robustness principle to be an immensely powerful way of figuring out how to approach many design problems. When it comes to figuring out what specific tools or technologies to use, there’s an equally useful principle: the rule of least power:

Choose the least powerful language suitable for a given purpose.

On the face of it, this sounds counter-intuitive; why forego a powerful technology in favour of something less powerful?

Well, power comes with a price. Powerful technologies tend to be more complex, which means they can be trickier to use and trickier to swap out later.

Take the front-end stack, for example: HTML, CSS, and JavaScript. HTML and CSS are declarative, so you don’t get as much precise control as you get with an imperative language like JavaScript. But JavaScript comes with a steeper learning curve and a stricter error-handling model than HTML or CSS.

As a general rule, it’s always worth asking if you can accomplish something with a less powerful technology:

In the web front-end stack — HTML, CSS, JS, and ARIA — if you can solve a problem with a simpler solution lower in the stack, you should. It’s less fragile, more foolproof, and just works.

• Instead of using JavaScript to do animation, see if you can do it in CSS instead.
• Instead of using JavaScript to do simple client-side form validation, try to use HTML input types and attributes like required.
• Instead of using ARIA to give a certain role value to a div or span, try to use a more suitable HTML element instead.

It sounds a lot like the KISS principle: Keep It Simple, Stupid. But whereas the KISS principle can be applied within a specific technology—like keeping your CSS manageable—the rule of least power is all about evaluating technology; choosing the most appropriate technology for the task at hand.

There are some associated principles, like YAGNI: You Ain’t Gonna Need It. That helps you avoid picking a technology that’s too powerful for your current needs, but which might be suitable in the future: premature optimisation. Or, as Rachel put it, stop solving problems you don’t yet have:

So make sure every bit of code added to your project is there for a reason you can explain, not just because it is part of some standard toolkit or boilerplate.

There’s no shortage of principles, laws, and rules out there, and I find many of them very useful, but if I had to pick just two that are particularly applicable to my work, they would be the robustness principle and the rule of least of power.

After all, if they’re good enough for Tim Berners-Lee…

Last month I went to CSS Day in Amsterdam, as an attendee this year, not a speaker. It was an excellent conference comprising the titular CSS day and a Browser API Special the day before.

By the end of CSS Day, my brain was full. Experiencing the depth of knowledge that’s contained in CSS now made me appreciate how powerful a language it is. I mean, the basics of CSS—selectors, properties, and values—can be grasped in a day. But you can spend a lifetime trying to master the details. Heck, you could spend a lifetime trying to master just one part of CSS, like layout, or text. And there would always be more to learn.

Unlike a programming language that requires knowledge of loops, variables, and other concepts, CSS is pretty easy to pick up. Maybe it’s because of this that it has gained the reputation of being simple. It is simple in the sense of “not complex”, but that doesn’t mean it’s easy. Mistaking “simple” for “easy” will only lead to heartache.

I think that’s what’s happened with some programmers coming to CSS for the first time. They’ve heard it’s simple, so they assume it’s easy. But then when they try to use it, it doesn’t work. It must be the fault of the language, because they know that they are smart, and this is supposed to be easy. So they blame the language. They say it’s broken. And so they try to “fix” it by making it conform to a more programmatic way of thinking.

I can’t help but think that they would be less frustrated if they would accept that CSS is not easy. Simple, yes, but not easy. Using CSS at scale has a learning curve, just like any powerful technology. The way to deal with that is not to hammer the technology into a different shape, but to get to know it, understand it, and respect it.

Emil has been playing around with CSS variables (or “custom properties” as they should more correctly be known), which have started landing in some browsers. It’s well worth a read. He does a great job of explaining the potential of this new CSS feature.

For now though, most of us will be using preprocessors like Sass to do our variabling for us. Sass was the subject of Chris’s talk at An Event Apart in San Francisco last week—an excellent event as always.

At one point, Chris briefly mentioned that he’s quite happy for variables (or constants, really) to remain in Sass and not to be part of the CSS spec. Alas, I didn’t get a chance to chat with Chris about that some more, but I wonder if his thinking aligns with mine. Because I too believe that CSS variables should remain firmly in the realm of preprocessers rather than browsers.

Hear me out…

There are a lot of really powerful programmatic concepts that we could add to CSS, all of which would certainly make it a more powerful language. But I think that power would come at an expense.

Right now, CSS is a relatively-straightforward language:

CSS isn’t voodoo, it’s a simple and straightforward language where you declare an element has a style and it happens.

That’s a somewhat-simplistic summation, and there’s definitely some complexity to certain aspects of CSS—like specificity or margin collapsing—but on the whole, it has a straightforward declarative syntax:

selector {
    property: value;
}

That’s it. I think that this simplicity is quite beautiful and surprisingly powerful.

Over at my collection of design principles, I’ve got a section on Bert Bos’s essay What is a good standard? In theory, it’s about designing standards in general, but it matches very closely to CSS in particular. Some of the watchwords are maintainability, modularity, extensibility, simplicity, and learnability. A lot of those principles are clearly connected. I think CSS does a pretty good job of balancing all of those principles, while still providing authors with quite a bit of power.

Going back to that fundamental pattern of CSS, you’ll notice that is completely modular:

selector {
    property: value;
}

None of those pieces (selector, property, value) reference anything elsewhere in the style sheet. But as soon as you introduce variables, that modularity is snapped apart. Now you’ve got a value that refers to something defined elsewhere in the style sheet (or even in a completely different style sheet).

But variables aren’t the first addition to CSS that sacrifices modularity. CSS animations already do that. If you want to invoke a keyframe animation, you have to define it. The declaration and the invocation happen in separate blocks:

selector {
    animation-name: myanimation;
}
@keyframes myanimation {
    from {
        property: value;
    }
    to {
        property: value;
    }
}

I’m not sure that there’s any better way to provide powerful animations in CSS, but this feature does sacrifice modularity …and I believe that has a knock-on effect for learnability and readability.

So CSS variables (or custom properties) aren’t the first crack in the wall of the design principles behind CSS. To mix my metaphors, the slippery slope began with @keyframes (and maybe @font-face too).

But there’s no denying that having variables/constants in CSS provide a lot of power. There’s plenty of programming ideas (like loops and functions) that would provide lots of power to CSS. I still don’t think it’s a good idea to mix up the declarative and the programmatic. That way lies XSLT—a strange hybrid beast that’s sort of a markup language and sort of a programming language.

I feel very strongly that HTML and CSS should remain learnable languages. I don’t just mean for professionals. I believe it’s really important that anybody should be able to write and style a web page.

Now does that mean that CSS must therefore remain hobbled? No, I don’t think so. Thanks to preprocessors like Sass, we can have our cake and eat it too. As professionals, we can use tools like Sass to wield the power of variables, functions (mixins) and other powerful concepts from the programming world.

Preprocessors cut the Gordian knot that’s formed from the tension in CSS between providing powerful features and remaining relatively easy to learn. That’s why I’m quite happy for variables, mixins, nesting and the like to remain firmly in the realm of Sass.

Incidentally, at An Event Apart, Chris was making the case that Sass’s power comes from the fact that it’s an abstraction. I don’t think that’s necessarily true—I think the fact that it provides a layer of abstraction might be a red herring.

Chris made the case for abstractions being inherently A Good Thing. Certainly if you go far enough down the stack (to Assembly Language), that’s true. But not all abstractions are good abstractions, and I’m not just talking about Spolky’s law of leaky abstractions.

Let’s take two different abstractions that share a common origin story:

• Sass is an abstraction layer for CSS.
• Haml is an abstraction layer for HTML.

If abstractions were inherently A Good Thing, then they would both provide value to some extent. But whereas Sass is a well-designed tool that allows CSS-savvy authors to write their CSS more easily, Haml is a steaming pile of poo.

Here’s the crucial difference: Sass doesn’t force you to write all your CSS in a completely new way. In fact, every .css file is automatically a valid .scss file. You are then free to use—or ignore—the features of Sass at your own pace.

Haml, on the other hand, forces you to use a completely new whitespace-significant syntax that maps on to HTML. There are no half-measures. It is an abstraction that is not only opinionated, it refuses to be reasoned with.

So I don’t think that Sass is good because it’s an abstraction; I think that Sass is good because it’s a well-designed abstraction. Crucially, it’s also easy to learn …just like CSS.