The Dilemma of Naming Font Size Variables

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Martin Lexelius on

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Normally, a project will have a set of pre-determined font sizes, usually as variables named in such a way that seeks some semblance of order and consistency. Any project of considerable size can use something like that. There are always headings, paragraphs, lists, etc. You could set font sizes explicitly and directly everywhere (e.g. font-size: 18px). Raw CSS, as it were. I do see that occasionally — mixing not just sizes but also units like px, rem and em in mindless chaos.

That’s why the CSS of a project typically uses variables or mixins — we’re shooting for structure, maintainability and, ultimately, consistency. We all know naming is hard and it doesn’t take looking much further than naming font size variables to see why. How should we name a small font size variable so it’s clear that it’s smaller than a large font size variable? And what happens if we need to insert a new variable in between them — is that one named in a way that clearly explains its relationship to the other size variables?

We’ll continue talking about naming font size variables in this post. But, really, the issue extends beyond font sizes to any sort of size or length value. Think paddings, margins, widths, heights, border radii, etc. These things need structure and consistency, too!

How do you define font sizes in your project? Does it look something like this with custom variables:

:root {
  /* Font size variables */
  --small: 12px;
  --medium: 16px;
  --large: 24px;
}

Or perhaps in Sass (which is what we’ll be using throughout this article) you might have variables for $small, $medium, and $large font sizes.

Fine. After a while, let’s say the designer adds a new <h1> heading for a hero section. And it is very large. Larger than anything you have in the project. No problem, you reply. You add an $xlarge to the project, and go about your day.

The following day, the designer makes a nice form label, which again has a new font size. This new size, though, is larger than small, but smaller than medium.

Here we go.

What should you call it? $small-medium? $small-2? $smedium? Whatever you name it, you won’t be happy with it. Because there is no word for that.

Or should you maybe refactor it? Create a new $xsmall, and change all instances of $small to $xsmall? And then you can use $small for the form label? There’s a small risk that you will forget to change somewhere and, hey, presto: a bug. What happens next time, when something is introduced that has a larger size than the $medium variable value? Do we have to refactor $large and $xlarge too?

I suggest adhering to a scale, always. An easy fix would be to further abstraction, perhaps ditching numbers and sizes in favor of functional names, like $form-label instead of $small-2 or $xsmall.

But imagine having a set of font sizes like this:

$small: 12px;
$form-label: 14px;
$medium: 16px;
$large: 24px;

That is a broken scale. It’s a size concept and a component concept mixed together. It raises questions. Should an alert or a button be allowed to use $form-label? Yuck.

Maybe you have a Greek thing going on, naming the variables $alpha, $beta, $gamma? Let me ask you then, what is then bigger than $alpha? $alpha-large? Or wait, is $alpha the small one?

I have also seen names like $button-font-size, $label-font-size, $blockquote-font-size. That seems to me like one variable per element used, instead of a scale, and sounds like it could be a lot of duplicated code if the same value is being used in multiple places, but with different names.

Perhaps you’re working with one base font size and percentages only? Sure, but I would say you need variables for the percentages. That’s how Geoff handles font sizing and even he admits that the setup raises his own eyebrows. Calculations with subjectively-named variables might be clear to you, but crazy-looking and complicated for anyone else jumping into the project.

h1 {
  font-size: clamp(var(--text-size-large), calc(var(--text-size-base) * var(--text-size-scaler)), var(--text-size-huge));
}

We need a better system

Adding and removing stuff constantly is the way we want to work. This is modern day development — MVP, Agile, and all the other hot buzzwords.

What we need is a scale syntax that allows room for changes. Adding a new size to the scale should be easy without introducing breaking changes. I’m thinking of a kind of scale that is both flexible and infinite. It must be more sophisticated than $small, $medium and $large.

It should be also be descriptive and intuitive. Preferably, you shouldn’t have to look up the variable names in the settings file or the config, or wherever you store these things. I don’t have the slightest clue if $epsilon comes before or after $sigma. Do you?

Using existing systems

Before trying to invent something new, is there an existing syntax or system we can leverage? Here are a few I’ve encountered.

International system of units

Surely, you’re familiar with terms like “kilobyte” and “megabyte.” Europeans are very used to “millimeter” and “centimeter.” Other examples are “giga,” “tera,” and “peta.” These prefixes can be used for length, weight, volume and more. Could a $centi font size work? It is intuitive to a certain extent, that is, if you’re familiar with the metric system. This is a finite scale. And there’s no room to add new sizes because they are already set.

Traditional point-size names

Long before computers and desktop publishing, books and newspapers were printed with lead type. The type setters had different names for different sizes. The sizes have a reference to a point size (pt) and could, in theory, be used for pixel sizes (px).

The type sizes in this system are called “Nonpareil,” “Pica,” “Cicero,” and “Great Primer,” just to name a few. The names are different depending on continent and country. Plus, the same name can have different sizes, so… quite confusing.

That said, I do like this system in a way because it would be like paying respect to an old craftsmanship from times past. But the names are so weird and specifically meant for type sizing, that it feels like a stretch to use for things like breakpoints and spacing.

Placing everyday objects on a scale

How about using stuff from our everyday life? Say chili peppers.

There are many kinds of chili peppers. The $habanero, is hotter than the $cayenne, which is hotter than the $jalapeno. That would be fun, yeah?

But as much as I enjoy the idea of writing font-size: $tabasco, I see two problems. If you’re not into peppers, you cannot know which pepper is hotter than another pepper — so, it’s not universally intuitive. Also, the bell pepper is 0 on the Scoville scale, and nothing is below that. Carolina Reaper is the hottest pepper in the world, so the scale is finite.

And yeah, peppers scale-wise are not larger or smaller, they are hotter. Bad concept. Maybe something more common, like types of balls?

There‘s a large range of different kinds of balls. You have handballs, soccer balls, volleyballs, etc. Need something larger than a medicine ball? Use $beach. Something smaller than a tennis ball? Use $pingpong. This is very intuitive, as I’d imagine everyone has played with all sorts of balls at some point, or at least are familiar of them from sports.

But is a ping pong ball larger than a golf ball? Who knows? Further, a bowling ball and a soccer ball are actually the same size. So… again, not perfect.

Scaling up to planets could work, but you would have to be knowledgeable in astronomy.

How about straight-up numbers? We’re unable to use numbers alone because tools like stylelinter will protest. But would something like this work:

$font-14: 14px;
$font-16: 16px;
$font-24: 24px;

Well, it’s infinite as there is always room for new additions. But it’s also incredibly specific, and there are some downsides to have the actual value be part of the name like that. Let’s assume that $font-18 is used in a lot of places. And now, they say, all places with 18px must be changed to 19px (because reasons). Now we need to rename the variable from $font-18 to $font-19 then change the value of $font-19 from 18px to 19px. And that’s before we finally update all places using $font-18 to $font-19. This is almost like using raw CSS. Low score for maintainability.

What about the animal kingdom?

Mother Nature has provided a myriad of species on this earth, which comes in handy in this situation. Imagine something like this:

$mouse: 12px;
$dog: 16px;
$hippo: 24px;

Need something smaller than a mouse? Use $bee, $ant or $flea. Larger than a bear? Try $moose or $hippo. Larger than an elephant? Well, you have the $whale, or heck, we can go prehistoric and use $t-rex. There’s always an animal to squeeze in here. Very versatile, very intuitive, also infinite (almost). And fun, too — I wouldn’t mind doing font-size: $squirrel. 🤩

But then again, even that might require needing to reference the variables, unless we know exactly which animals are contained in our zoo of font sizes. But maybe that’s not a big deal as long as it scales.

I have spent way too much time pondering this

Or have I? The code base is where you spend your working hours. It’s your work environment, just like chairs and monitors. And the workplace should be a nice place.

How do you handle your font size scales? Do you have one system for fonts and another for things like margins? Can anyone jump right into your code and understand how everything is organized? Please tell in the comments!