from Hacker News

Ask HN: How do you – Style Components built using React/Vue/Angular etc.

by sunnykgupta on 5/30/17, 3:19 PM with 6 comments

UI developers till a few months back were writing styles in a separate SASS files which would compile down to CSS and be included into the HTML.

With modern frameworks, developers started writing their styles in the HTML directly. It felt natural to new developers who liked keeping their HTML/JS for a component in a single Template/JSX file.

In my 'opinion', inline-styles polluted the DOM and get in the way. Browsers have to take a break while laying out to process each inline-style they encounter with the DOM nodes.

Keeping styles for each component in their own JSX makes it difficult to visualize the entire hierarchy in a large project. It is very easy to visualise in case of a SASS file (if done properly.)

Enter, styled-components which lets you write CSS as templates in JS and auto assigns a unique class name to every component. Hence no more element level styles. It also auto links the class to every instance of the component.

Under the hood, we are adding <style> nodes via JS and the browser has to generate the same class during every execution of the app/page (showcased as a feature - no build process). IMHO, this does not seem to bring in any advantage over the fact that browsers can easily parse external stylesheets once and cache them.

Consider the case where you are creating a UI framework from scratch. You would encounter nested elements, e.g. button inside a modal needs to be different than a button inside a hero component.

Of course having the ability to add custom CSS via JS is a good feature to have. Would you use it while building a React version of Bootstrap from scratch or go with a tool like SASS to create the styles for such a framework?

Looking for inputs from developers who work on modern UI/Frontend on how you handle styles for your components.

  • by sahrizv on 6/2/17, 3:06 PM

    I think a global style file helps when the same HTML markup is repeated in several parts of your application.

    However, a component based architecture, by definition represents the reusable HTML markup of your application. Since such a component brings along its own styles wherever it is used, there is negligible loss of reusability of styles.

    This is in theory of course, but my experience (with Vue.js) has been the same in practice too.

    With Vue.js at least, you have the optional "scoped styles" feature which gives you tuneable reusability in case you really need it. Most of the time, I find my self writing

      <style scoped>/*styles here*/</style>

 in my component files.
    Edit: Regarding performance, I believe it could potentially be an issue on mobile devices (for now), and if so I would solve it by creating a global stylesheet by merging all individual stylesheets and appending the component name as a prefix in all selectors in both the styles and the markup.

    This would be done programmatically using webpack or some other front end build tool. I doubt I'd ever need to do that TBH.

  • by mmdonaldson on 5/30/17, 11:21 PM

    As the front end community moves to a decentralized component based model, it doesn't make sense to keep your styles seperate. Being able to see exactly what a component does, how it renders, how it looks, how it manages state, in my opinion has these benefits:

    1 makes the code easier to test 2 easier to onboard new developers 3 better developer experience 4 easier to scale 5 easier to create decoupled chunks for single page apps/progressive web apps.

  • by gitconnected on 5/30/17, 6:15 PM

    Styles in components are the next pattern to be figured out for components. The considerations should be

    1. Styles should only apply to the component that they intend to style 2. Keep styles decoupled from any specific component library 3. There needs to be a communication layer between application interactions and the styles applied 4. Provide scalable patterns 5. Cache styles effectively 6. Chunk styles to optimize site

  • by sunnykgupta on 5/31/17, 6:55 AM

    I agree with most comments which say that the modular approach is good for maintainability. But what about performance that takes a hit when the JS is creating and linking styles. Also, browser caching of styles is not possible in these cases.