By default Gatsby drumps all the css required on a given html document into its header making css caching impossible:
import "./foo.css"
import "./bar.css"
results in:
<style data-href="/styles.f6ce41623bc6fbf912c0.css">
.foo{color:green}.bar{color:orange}
</style>
/styles.f6ce41623bc6fbf912c0.css contains exactly that stylesheet.
is there a way to keep foo.css and bar.css in separate files without loosing the ability to minify and autoprefix everything?
The functionality is called bundling, and Gatsby uses Webpack to do it. You could alter the Webpack configuration, but I’d say there is really no point in doing that.
Bundling and code-splitting resources is a crucial part of why Gatsby is so fast. By bundling the CSS for every page makes sure that only resources required by the current page are loaded. Gatsby also caches all of the resources it has loaded, so you don’t need to worry so much about resource economy.
I found a code snippet from a Gatsby issue comment, which replaces inline <style> elements with <link>s, but I wouldn’t recommend doing that without going through some performance measurement.
Related
I just committed and pushed a minor CSS tweak. On my server I git pull, npm run build, and forever restart __sapper__/build
Now there seems to be more than one version of the same CSS rule across different files, as per the below screenshot (this is after disabling browser cache):
The correct rule is the third one (vertical-align: top; margin-top: 1px;), which seems to be a combination of CSS files.
Any idea where the 'old' rules are coming from? Cached somewhere somehow?
/EDIT This is my rollup.config.js: https://gist.github.com/Bandit/bbcfd6c70ace5800765313dfe6021854
/EDIT2 The styles in question are in a /style/global.scss file, which is included using the following code in /routes/_layout.svelte:
<style lang="scss" global>
#import "./style/global.scss";
main {
background-color: white;
padding: 5rem 1rem 0 1rem;
}
</style>
Guessing this is somehow the issue? Where is the right place to 'inject' global stylesheet for colours/theme/typography etc?
/EDIT3 The styles being included via _layout.svelte are being included more than once in dev as well, here's a screenshot:
These selectors don't seem to come from a Svelte component, since they're not scoped (e.g. .split-button.svelte-a9ylb1)? Or are you using :global(.split-button) in a Svelte component?
Anyway... I failed to reproduce your issue, but my intuition is that your problem probably comes from the postcss plugin. It has an inject option that is enabled by default. What this option does is injecting a <style> tag in the <head> of your doc; the code that does this is appended to your modules' JS by the postcss plugin. This behaviour might very well clash with what svelte-preprocess or rollup-plugin-svelte is doing.
Try adding inject: false in the 3 places where you're using postcss in your Rollup config, and see if this helps.
Another possibility might be the service worker. I don't think an issue there could produce your result you get, but we never know... You should try options like "Update on reload" and "Bypass for network" (I don't know what are the equivalent options in your browser) to see if that makes a difference.
Otherwise, you may have to show more of your code. Where does this precise CSS rule come from (e.g. style tag in a Svelte component, SCSS file in node_modules, ...)? How is it imported into your project (e.g. import './app.css', #import './app.scss', etc.), and where? Also, I'm surprised that you have the postcss rollup plugin only in the server (the one that is not registered in sveltePreprocess)... What do you need this for, that you don't need on the client?
EDIT: Follow up
Wait, what? You've got some style files under your routes directory?? routes/style/global.scss?
Even with that, I don't appear to be able to reproduce your problem, but it's worth noting that Sapper will try to include every file it encounters under this directory. If you've got a plugin that lets you import *.scss files, then Sapper will actually see a global.scss.js, so it will think it's a server route. Without a plugin that can eat SCSS, it should... crash. If the plugin in question is postcss with its default inject option still to true, to me it looks like a star suspect...
Anyway, some further points of clarification...
svelte-preprocess enables lang="xxx", global attribute in <style global ...>, in .svelte files only.
rollup-plugin-postcss can additionally be added, directly in plugins array (i.e. not as an option of svelte plugin). It gives support for import './foo.scss', in .js files, as well as in the <script> part of .svelte files.
(Of course, SASS support by PostCSS, or PostCSS support by Svelte preprocess are depending on the config you feed them.)
OK. So now there are multiple places where some CSS / SCSS can enter your build. That I can think of, there are the following ways:
<link rel='stylesheet' href='global.css'> in src/template.html: this one will copied as is without processing.
I suppose you can also have such a "custom" <link> tag in the markup (~HTML) part of a .svelte file, and it would be included as is in the resulting HTML (you'd still have the responsibility that the reference CSS file be accessible at the given URL).
import 'something.css' or 'import 'something.scss'in a.jsor JS part of a.sveltefile: these will get processed by bundler & plugins, and converted to some JS code, with optionally additional assets that the JS can reference (typically, a proper CSS file is generated, and some JS code dynamically injects atag for it at runtime; another approach is to generate some JS that will inject every CSS rule in the doc). PostCSS withinject: true` uses the CSS + inject tag method.
the CSS / SCSS style that you write in the <style> part of a .svelte file will also be processed by the Svelte plugin in a similar way as described just before (preprocess option required to accept anything else than raw CSS); depending on the plugin configuration, it may also try to write a '.css' file for your application (see docs. With the emitCss option, that is apparently needed for Sapper, it should output one CSS file per component (or maybe entrypoint).
In your case, you say that you've removed rollup-plugin-postcss from your config, so the 3rd point (import css from js) should not be possible anymore.
Well... I just hope this can help you investigate further.
I've pushed a Sapper + PostCSS example on a branch on this repo. As far as I can tell, it doesn't have the issue you're describing here. So maybe you can find the problem by comparing with what you have. See this commit for the diff with the vanilla official template.
I tried to also add rollup-plugin-postcss, like you initially had in your config, in order to be able to import .scss from outside of Svelte components. But I failed to find a way to do this that don't conflict with Sapper.
EDIT 2
Oh, and just to be sure... Be sure to try a little rm -r __sapper__ && rm -r src/node_modules/#sapper (notice: node_modules under src, not the one in your project's root) before pursuing your investigation. I'm sure you've already done that, but better safe than sorry. Stale things can live in there.
I have built my app with React Boilerplate, and have been surprised to find all my CSS modules are not generating CSS as I thought, but the CSS is instead generated from JS and embedded in the header of the page. The image below shows just some of the many, many style elements that appear in my header after the page has loaded.
For development, I can see this making sense for HMR etc. However, for a production build, it is not what I would expect.
I would think the most performant build (ie, best) would be a static CSS file alongside the js. In fact, in our production build there is a lot of stutter as the site loads and applies styles to the elements in a staggered manner.
It seems straight-forward to build a static CSS file, so why isn't it the default (especially for RBP, whose major claim is that it is production-ready). After 5 mins of searching I found https://github.com/webpack-contrib/mini-css-extract-plugin, which seems to do exactly what I want.
Is there a benefit to dynamically adding the CSS in the document header as pictured? Is there anything we would lose if we built a static CSS document instead?
I'm using CSS Modules (Sass) with rollup on a component library project, which is working well. Each component ends up with a dist folder containing a single JS bundle file, and a corresponding CSS file with the scoped CSS classes so consumers of the component don't have to worry about CSS class name conflicts. All they do is include the JS bundle and the CSS file and everything is great. Yay CSS Modules.
The problem I'm now facing is that some components really need separate "themes" - ideally, separate CSS files, one per theme. So consumers can continue as they've been doing: including the JS bundle, but now choosing which CSS file to include to pick a theme.
I'm not sure how to get this going with CSS modules & rollup, and whether this is even the sort of approach others are taking. From what I can see, rollup always handles bundling things together, whereas I want separate CSS files, all of which get their classes renamed identically during the build phase. That way, if within my JS I refer to styles.myclass, if myclass had gotten renamed to scoped-myclass by CSS modules for the original CSS file, for a second CSS file it would also get the same name.
This would keep consumption of the component extremely simple - just a matter of including a different CSS file.
Any suggestions?
Awfully late, but let me answer this 3 years on. So what I ended up doing was totally detaching the CSS generation step from rollup and relying on the Sass CLI to handle that portion of the build process. It felt a bit klutzy, but I remember it wasn't awfully hard to do and solved the problem I outlined above. I don't believe there was a plain rollup solution at the time, nor do I think there's one today.
However... in my case the whole approach was kinda mistaken. This certainly won't be everyone's scenario, but let me spell it all out because hey it may be useful and it definitely wasn't obvious to me at the time.
This was for an in-house shared component library, where each component and its corresponding CSS was a separate npm package stored in our Artifactory. When it grew, plenty of internal references popped up, e.g. multiple components would reference the Button component, and over time they'd reference different versions of the Buttons component - each of which needed its own properly scoped CSS, unique to that package-version.
So what I found was that by doing it this way - having the CSS generated as part of the npm package dist files - I had to write an additional layer for the consumer applications that would parse their node_modules/ folder for our own internal components and combine all the different CSS files, such as the multiple versions of buttons. e.g. the main application would directly import buttons v1.0.0 in its package.json file, but the Dialog component (also included in the package.json) could include buttons 2.0.0 as its own dependency. For every version of the package, there was a uniquely scoped version of the CSS - so the consuming application HAD to include every version otherwise the styling would be borked.
So all in all, it ended up being way more complex that I wanted. I thought I could make it easier & better with the separate generated themed CSS files as part of the package dist, but it didn't end up that way. If I could revisit that project today, I'd re-examine a solution used by Material UI and others which I kinda poo-poo'd at the time: automatic injection of the CSS into the page by the component JS, rather than generating standalone CSS files which required extra work by the consumer applications to gather up and add to the final webpage. Frankly, now I regard it as the "least crap". There are definite downsides to the injection approach (extra work done on every page render for everyone! Yikes!), but there's no doubt in my mind it hugely simplifies the job of the consumer applications. It's a balancing act, but in 20-20 hindsight I'd lean towards the injection approach. With that, scoping & theming is a different and much simpler problem.
If I got you right, consider looking at SCSS plugin: rollup-plugin-scss. It captures all spare .css files imported in the components, and then processes them through underlying node-sass. The catch is, it seems like you can write a custom callback function that'd handle your CSSs differently based on conditions you throw in.
Based on the example from the plugin's page:
import scss from 'rollup-plugin-scss'
...
export default {
input: 'src/index.tsx',
output: [...],
plugins: [
...
output: function (styles, styleNodes) {
// replace this with conditioned outputs as needed:
writeFileSync('bundle1.css', styles)
writeFileSync('bundle2.css', styles)
},
]
}
I have been reading about leveraging cdn to boost the speed of web application. I am developing a react application and I am using stylus for css. My current structure of project is something like this: Each component or page has it's own seperate local stylus file. So this way I am trying to keep the syles isolated for each component so that it is easy to maintain. But mostly all the stylus files has around 1000 lines of code which is common for all the stylus files. This brings down the speed of my application while it loads. I am thinking of putting the css on cdn. This way it will be faster I am assuming. How can I do it with my present project structure?
Right now I include stylus like this in each component
import c from "./reviews.styl"
render() {
return (
<div className={c.container}>
If I create a seperate css file as sugegsted in answer to include all the common css, how will I say to each component to use that common.css file. Each component is already using the imported stylus file like I shown above
You have a few ways here...
In the constructor you can append a link tag to the head
In componentWillMount you can append a link tag to the head
e.g.
document.getElementsByTagName('head')[0].appendChild('<link rel=stylesheet href=mycdn.com/mystylesheet.css />');
I'm not saying moving your CSS to a CDN is a good solution, but this is how you'd accomplish it.
The benefit of a CDN is that your static web assets are deployed across the world on multiple servers and your users can easily retrieve quick copies of these assets. In the case where you are using a file like jquery-x.js, users may already have retrieved the file from the CDN for another website and even on the first page load, they can use a cached copy.
Your biggest issue is the duplication of CSS code throughout each component's style page and that can be overcome by just creating a generic style sheet with the common styles (say "common.css") and then including it in each component. You don't have to use a CDN to achieve this and you can investigate CDNs after you first get rid of the duplicate CSS as another way to speed up your page load.
I know that there are questions regarding this same topic, but for HTML. What are some good conventions in regards to using external stylesheets in a Flex app.? How would you break up the stylesheets (names of stylesheets and what they include)?
Flex compiles the external CSS file when you publish your project.
There is a way to load CSS at runtime using Flex; it can be done by compiling CSS files into SWF files and load them at runtime using StyleManager.loadStyleDeclarations.
See the LiveDocs on Stylesheets at Run Time for more info.
Some conventions we use in organizing stylesheets:
Have one main.css stylesheet that holds all of the data for skinning the base application.
Have one fonts.css stylesheet to store all of the fonts in the main app, because these can get quite messy.
The main.css stylesheet is included in the main swf via the <mx:Style source="main.css"/> tag. We load our app with as little as possible, and once everything is loaded, if we need to immediately show some text (sometimes we just have a video playing if it's an advertising site), we fade/tween in the main elements and load the fonts.css via StyleManager.loadStyleDeclarations at runtime.
If we have an admin panel, we have an admin.css stylesheet which we load at runtime because the main app doesn't need it.
We don't need to divide up the CSS anymore than that because we usually create a whole set of skins in a Theme, so the stylesheet is just applying those skins to components and is pretty lean (using Flex 4). I tend not do divide stylesheets into anything smaller (like "pages.css", "comments.css", "popups.css", or even "controls.css", etc.) because it would be overkill and too much to manage for little in return. That's common with HTML, but that's because HTML requires CSS for nice presentation; Flex could do without CSS entirely.
When developing, one of us usually develops most of the skin right away (having a default wireframe setup, like those found on ScaleNine as they do the photoshop/flash/after-effects. There's no way to not have to recompile the css swf if you make changes. But if it is loaded at runtime, you only have to recompile the css file and not the main swf, which is useful but not really useful during hardcore skin development.
I tried keeping the main stylesheet separate during development (in a custom Theme), and it made development a LOT harder, because I had to recompile the css separately every time I made a change and sometimes I had to recompile the main app too, and there were strange and hard-to-track-down bugs, etc. Then I was compiling two different apps. So I recommend keeping the main css file part of the main app.
If you wanted runtime css without having to recompile anything, try Ruben's CSS Loader and check out the source. But that would come at a runtime performance cost.
Flex is not something I've dealt with, but I did some research. It looks like the code to call a remote stylesheet is this:
<mx:Style source="com/example/assets/stylesheet.css" />
Flex Quick Start: Building a simple user interface: Styling your components says this:
Note: You should try to limit the
number of style sheets used in an
application, and set the style sheet
only at the top-level document in the
application (the document that
contains the tag). If
you set a style sheet in a child
document, unexpected results can
occur.
The implication of this seems to be that multiple stylesheets are not really possible. It sounds like what you want to do is organize your stylesheets, check out Organizing Your Stylesheets and Architecting CSS for some ideas for approaches. It looks like you have classes and basic tags, but the W3C stylesheet specifications are different from the Flex stylesheet specification.
As a non-Flex developer, Namespaces looks interesting as a way to organize namespaces: How to use the new CSS syntax in Flex 4.