Comment by talmand | Hacker News Reader

Comment by talmand | Hacker News Reader

I'm sorry but I totally fail to see the problem that this is supposedly trying to fix.

In the example provided, the problem is presented as a failure of cascading in CSS. But the problem as I see it, is in the structure of the HTML. The example is a component with a button inside a component with a button. Then global selectors are used which creates a result we don't want.

Slide 11 states global selectors are a problem. Which they can be, if used improperly just like every other tool we have access to.

So, the solution is to write Javascript that results in using classes. Which is what should have been done in the first place.

So, instead of creating a proper class structure in the HTML it is suggested to use Javascript to create classes, inject style sheets into the dom, and inject classes into the HTML elements on page load?

All to avoid using CSS properly?

I'm sure this is a wonderfully coded project, has interesting ideas, and may be useful to some, but as a front-end developer I seriously doubt I would ever use this nor recommend it. I would suggest just learning CSS, it's not that hard.

I would say that this type of project would be far more suited for a back-end library that generates stylesheets on the fly in an effort to maintain code efficiency. But doing all this in Javascript just seems to be about addressing people's attitude towards CSS and not about actual problems in CSS.

Manually ensuring class names don't clash only scales so far.

The problem this tries to address is the problem of maintainability when the entirety of the codebase doesn't fit in your head (because you have many people committing CSS at a fast pace, or a lot of junior devs, or because the codebase is large, or old, or the deadline is too tight, or any other number of reasons)

There's a world of difference between Facebook with its hundreds of devs commiting code to the same codebase over the span of many years, vs an agency where it's typical for one frontend person to own the entirety of the CSS codebase for a month-long project. In the latter case, you usually don't need the ability to scale the team (or can get away with enforcing ad-hoc processes). In the former case, having tooling that enables non-clashing class names by default is worth the trade-offs.

Creating a more verbose and complicated tool won't solve the problems you describe, they are still there but only masked until it becomes an even bigger problem.

I would be the first to agree that there are problems with CSS, I use it nearly every day and I run into these problems quite a lot. But moving to the JS to attempt to solve these problems is taking several steps backwards to me.

All the problems you list in your example I would say exist as potential problems in any other aspect of a large-scale project. In most of the examples I've seen the problem seems to be giving developers who don't know CSS access to CSS and then wonder why it eventually falls apart.

I agree that solving these problems at a higher level would work better than this.

Scoped CSS[1] would have been a good start, but unfortunately it looks to be in trouble (removed from Chrome).[2]

[1] https://html.spec.whatwg.org/multipage/semantics.html#attr-s... [2] https://www.chromestatus.com/features/5374137958662144

Please admit that css is a mess.

You can't have proper modules that you just plugin in. I want a button styled a way... it will mix with some other default button. I have to create many button classes.

I admit CSS is a mess, I've never denied it. I simply disagree that a system similar to this approach actually solves anything in the long run.

But you can have proper modules that you just plugin. If you plop in your button and it conflicts with someone else's button; then one of you did it wrong. The solution is to create multiple button classes as you say, but this Javascript solution does the exact same thing.

>but this Javascript solution does the exact same thing.

But with this lib I don't care about classes. I just put thing in, and I have 0 conflicts. I can do whatever I want and no conflicts. Try that in css. Also take a look at react.js this lib is perfect fit for that.

Yup. Pretty much any virtual-dom approach benefits from this type of solution. Furthermore, if you adopt any sort of system on top of the v-dom approach that does layout management with CSS 3D matrices like famo.us does, you end up greatly benefiting from a solution like this as well. Cascading doesn't work really that well if you don't have explicit and persistent semantic nesting all the way down the tree of elements in a window.

The code you write doesn't care about classes, but the CSS that is generated does. Why not do it the CSS way from the beginning and take JS out of the equation altogether so that everything is more efficient?

The most common answer I've seen is "because I don't want to learn CSS", which I don't feel is a good enough answer.

I can write CSS all day using classes that do not conflict in the manner described.

There is another answer pointed out multiple times throughout this thread which is "because name clashes happen if we want to write components in isolation from other teams". Its just that the "writing separate components" part never happens exactly because the infrastructure doesn't support it (except in situations of dire need like fontawesome), so there are "no problems" :)

I'm not claiming this or the vjeux's system (from the presentation link in my other post) are silver bullets, just that they are attempts to solve this specific problem. I'd argue that the reasons presented in vjeux's presentation are not of the clueless-developers-writing-crappy-css variety, although I do concede Facebook-scale problems are not common in the industry.

Personally, I agree that deviating from CSS syntax is not a viable solution for a large number of cases, and neither of those solutions is perfect. I just think it's cool that people are experimenting with different ways of creating collision-resistant styling tools, rather than sticking w/ the status quo.

I think they are interesting as well, but if I see a problem being created in an attempt to address a problem then I say so. I'm sure many of the thoughts and ideas of such projects can be integrated into CSS to make it better, but they will be integrated into CSS. I would propose the author take this system and roll it into Grunt, or similar, where it would be much more useful as opposed to client side. You should see from my other comments on this topic that the majority of my objection is that it is a client-side solution which I think is the wrong approach.

How does one properly use classes without making them global? Its either global or tied to your document hierarchy. And tied to a hierarchy is worse because it makes it harder to reuse a class outside that particular hierarchy without modifying the original selector...

You don't. That's the whole point. The reason for classes is to reuse CSS properties for efficiency. If you are making classes that are strictly tied to your hierarchy in a way that prevents proper reuse, then it's being coded the wrong way. Using a tool to fix the improper usage of another tool is not the solution.

If this tool is the solution, that the CSS it generates is the best way to do things, then why not code the CSS that way in the first place?

EDIT: As I'm seeing elsewhere in this thread; why exactly is globals bad in CSS?

Globals make it impossible to reason about separate components in isolation. What classname can I use for this button? Can I use '.button'? What if someone else already uses '.button'? Who knows...

You can namespace all CSS rules. It's annoying in CSS, but really easy in LESS and SASS.

e.g.

  my-namespace {
    .button {
      color: red;
    }

    .another-button {
      color: blue;
    }
  }

The namespace can be a custom element name, a class or an ID.

The problem with this approach is that you need to declare the namespace in DOM somehow, and depending on the project that can either be easy or rather difficult. I used this technique when I ported a stand-alone application with classes just like ".button" to be a single page in a larger application, and it worked fine.

Anyway, I do think that CSS should have a proper solution to modularization.

EDIT: Now that I could open the link (it didn't open for me previously), I now see that this approach doesn't solve the problem with the article, since it doesn't support nested namespaces. (Although a hacky solution would be a 'reset all rules' helper in the inner namespace).

I have a project now, with multiple developers, that uses this system; we've never had any conflicts in our CSS and I seriously doubt we ever will. It's mostly component driven with the occasional global selector.

As for your example not working with the approach, that's one of the problems as I see it with these solutions. The fancy, complicated approach apparently doesn't support one of the basics of CSS which would go a long way to fixing the problem as they see it.

What if component A and component B need that button? You will comp-a,comp-b{.button{}}? Will you save in comp-a-and-comp-b.scss? What if you need in comp-c and comp-d? As you can see your button is not tight to that comp.

I prefer to have a button class, for example in react that when instanced renders all the time the same. It boundles it's css within, just like this lib.

You could use the namespace feature of Less for that:

http://lesscss.org/features/#features-overview-feature-names...

I haven't personally used it, though.

Another solution would be have a "button.less" like this:

  comp-a, comp-b, comp-c {
    .button {
    }
  }

There's nothing stopping you from doing any of that with CSS today, especially if you use SASS or LESS.

SASS and LESS are CSS DSLs, you are doing limited programming with CSS, at that stage you may as well do programming in a Turing complete language like JS and reduce the number of tools in your tool chain.

As spion says with web components on the horizon, and with current frameworks like React, having classnames live in the global namespace makes creating reusable components that don't clash with other components impossible.

I have a hunch some consensus will evolve that will use Java/AS3 namespace prefixes to enable sharing, so instead of .button you'll have something like .com-github-dougmartin-button.

Or even better, namespace the classes with nesting; which you can today with or without a prepocessor. Such verbose classnames is not necessary.

Yes, namespacing is the best currently available option. Unfortunately its only an approximation of lexical scope, as the example in the presentation shows (the one with the two red buttons).

True, this is not something that happens often, and we can mostly get away with namespaces. But that's not the point. The point is that lexical scope is a tried and proven (by years of research, in multiple languages) solution to this problem which doesn't have any of these quirks. And JS has lexical scope.

The example with the two buttons is inherently flawed and is a bad example. It specifically creates an easily preventable problem in an effort to show a solution to that problem.

There is nothing that this library can do that I cannot hand-code in CSS myself. Because it has to generate the CSS that the browser expects to get, which is not hard to do.

The answer is LESS or SASS but for the love of god NOT JS. If you are concerned with breaking cascading then...

.default-button(){ // properties }

.component-a button { background-color: red; }

.component-b button { .default-button(); color: green; }

.default-button is still global in that example and may be accidentally overridden by someone working on another part of the site.

Which is actually quite true, but that problem lies with the person who overwrites the properties. That is not a problem in CSS. The most I would say that the HTML structure and CSS classes was not properly planned out to help prevent such things.

It can be done, it's just most examples of this type of thing is more along the lines of "I want to do it my way!", which is not always a proper way to go about things.

Its definitely not a problem with the person. That person may be working on a, say, date picker component (or something equivalent that is not yet covered with HTLM5) that provides minimal styling (with the ability to override it). They don't even know all their end-users.

They decided to use the name `.calendar`. Was that safe? Nope, their user #3 had an "upcoming events" calendar using the same class name that totally breaks when the datepicker CSS is included on the page. Should they make sure to prefix all their class names with their name? What if someone else with the same name also decides to do this? What if they make a new alternate datepicker, must they add the version number/descriptor too?

This is probably one of the reasons why we don't yet have separate reusable components with minimal overridable styles for the web (instead we have only entire pre-styled frameworks)

If styles had scope and HTML had a way to import them, we could say `import calendar from "path/to/file"`, then use the calendar style on our component and be sure that there is no way its going to leak outside of outside its lexical scope. Web components will fix this (html imports, scoped stylesheets). But web components aren't ready yet.

Let me ask you a different question though: is there a reason for the "oh god, not JS" sentiment? The solution is potentially even simpler than CSS: styles are defined as variables containing JSON objects, they're exported as a module, and can be imported and used by any component and mixed freely. No cascading/selector rules, no priorities, no overrides. When HTML CSS and JS share scope, things become much simpler.

I do have a reason for saying "oh god not JS". In my experience, the biggest reason people try and solve CSS issues with javascript is because they don't fully understand CSS and how to structure it in a maintainable way.

I used to hate CSS. I still think it is very flawed, just google how to center something and watch all the blogs pop up.

But rather than cursing it the rest of my dev days, I took the time to learn it and structure it properly. I now never spend longer than a few minutes trying to resolve a css bug.

Ideas like the OPs only procrastinate someone's true problem, which is they don't know how to properly work with the technology that they are forced to work with.

Your example only shows to me problems in the person and/or the team doing the CSS coding. It is certainly possible to namespace CSS if guidelines are established at project start, just like with coding any other language. What happens if two developers namespace their class in the same way?

The reason I would say no to a JS solution is simply because you are adding yet another step to the render of the page, more code for the browser to parse, and in the end results in the same issues you started with as they are only masked. This is just an attempt to make something work in a fashion it was designed to do. I'd rather fix the problem at the source instead of adding another layer to the problems.

But in the end, no matter what fancy JS code that comes up it still has to render out the CSS exactly as the browser expects it to be. That means that whatever this thing generates, people who know CSS can hand-code the exact same thing. Any problems that exists for CSS exists in this as well, it just masked so it's not readily apparent.

But what if there isn't a single cohesive team developing the website? There are no globally established practices for CSS name-spacing and there are multiple ways to do it (based on what tradeoffs you're willing to make).

See font-awesome for an example of what I mean by library (yes, they prefix everything with `fa-` which is fine until the bootstrap team comes up with a FizzActivity widget in bootstrap, which you wont be able to use together with fontawesome)

What happens if two developers namespace their class in the same way in JS? Well, with CommonJS this is pretty much impossible (import by path), and even without CommonJS there is no incentive to do it as you can easily pick a huge namespace without it affecting anyone. Just adding `var shortName = long.namespace.containing.shortName;` fixes the long name without that short name having effects anywhere else in the code or any of the inner functions (components) you may call, because... lexical scope.

And sure, we can hand-code everything in assembly too - after all thats what compilers do anyway. But that doesn't mean that the higher level language has all the problems that assembly has. A tool like this can do a lot of the job for you, by generating unique names and letting you refer to them via any (variable) name you like.

I don't see the difference between your concern and being concerned with a green developer changing some base class (in java for example) without fully understanding how those changes will affect the rest of the application. You can introduce bugs that a compiler won't catch.

It seems to me your main problem is how do you have people who don't know what they are doing perform like an experienced developer/designer.

So you css will have the same structure as html.. Therefore why not putting your css in your html. Well, in this case you should put the css in the javascript module which renders the html and then the css.

The example I provided above aggressively overwrites any inherited CSS properties for some component B.

Example 1:

<div class="component-a"><button></button><div class="component-b"><button></button></div></div>

Example 2:

<div class="component-b"><button></button></div>

Result:

The <button> wrapped in div.component-b for both above examples will render exactly the same, ignoring html structure.

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