Benefits of using styled-components in React

Editor’s Note: This article was updated with relevant information in July 2021, including styled-components’s current GitHub rating and additional benefits and concerns around using styled-components.

In this article, we will be looking at some of the various benefits of styled-components and why you should consider adopting it as your preferred CSS-in-JS framework.

What is styled-components?

Styled-components is a CSS-in-JS styling framework that uses tagged template literals in JavaScript and the power of CSS to provide a platform that allows you to write actual CSS to style React components.

Styled components are easy-to-make React components that you write with the styled-components library, where you can style your components with plain CSS inside your JavaScript code. On the official documentation page, you would see the example below:

const Button = styled.a`
  display: inline-block;
  border-radius: 3px;
  padding: 0.5rem 0;
  margin: 0.5rem 1rem;
  width: 11rem;
  background: transparent;
  color: white;
  border: 2px solid white;


  ${props => props.primary && css`
    background: white;
    color: palevioletred;
  `}
`

render(
  <div>
    <Button
      href="https://github.com/styled-components/styled-components"
      target="_blank"
      rel="noopener"
      primary>
      GitHub
    </Button>

    <Button as={Link} href="/docs" prefetch>
      Documentation
    </Button>
  </div>
)

We can clearly see the button as a JavaScript variable and the styles defined in backticks are plain CSS styles. We also see the nested style property with plain CSS styles. This is how styled-components renders CSS in JavaScript.

I know the subject of CSS-in-JS is heavily debated in the frontend community, especially among React developers, so I’d ask that you keep an open mind.

Styling React components

There are many ways to style a React component. There’s the traditional way of using CSS in external CSS files, which then passes a string as the className prop to reference them, like so:

render() {
  return <span className="menu navigation-menu">Menu</span>
}

If you have worked with a large web application, you can attest to the fact that the CSS files begin to get bulky, clumsy, and complex. One great solution to this is the introduction of SASS. Although SASS helps, you’ll eventually deal with the same issue due to the sheer number of SCSS files a project can have. Even the abstraction starts to become complex in itself.

You can also inline CSS inside your React components:

const divStyle = {
  color: 'blue',
  backgroundImage: 'url(' + imgUrl + ')',
};

function HelloWorldComponent() {
  return <div style={divStyle}>Hello World!</div>;
}

This method is highly discouraged by React, as it is neither sustainable nor scalable (more on this later).

Finally, CSS-in-JS is a technique where JavaScript is used to style components. When this JavaScript is parsed, CSS is generated as a style element and attached directly on top of the DOM.

There are a host of CSS-in-JS frameworks out there: styled-components, Emotion, JSS, Radium, Aphrodite, and more. You can see a comparison table here. Styled-components is, however, arguably the most popular. This option looks promising — it’s no wonder there is a very fast, widespread adoption, with over 600k downloads in the past month.

Why you should use styled-components

Freedom to build custom components with CSS

With styled-components, the UI design’s focus shifts from merely styling HTML elements or React components through className to defining styled components that contain their own styles and are easily reusable across the entire project. So, initially, a sub-heading declaration that looked like this:

<h2 className="subTitle">Gucci Snakes </h2>

With the styles defined like this:

h2.subTitle{
  font-size: 2em;
  color: blue;
}

Would become something like this:

import styled from 'styled-components';
const Subtitle = styled.h2`
  font-size: 2em;
  color: blue;
`;
<Subtitle>Gucci Snakes</Subtitle>

The styles become an integral part of the component here, thereby eliminating the key part the CSS classes initially played by removing the mapping between styles and components. This is all built with plain CSS, so there is always a feeling of familiarity you get when working with something you are already used to.

This feeling has been carefully preserved for every user of styled-components, as the syntax is still largely plain CSS.

Inline styling on steroids with styled-components

Ordinarily, inline styling is discouraged by the React team, a concern that is valid because inline styles do not allow the use of pseudos and media queries. Also, inline styles should not be used due to concerns about browser compatibility, camel-casing, and automatically appended scalar quantities.

But with styled-components, we can see a kind of inline styling but without all the aforementioned inline styling baggage. I call it vibranium power. Here is sample code to demonstrate:

const paragraphStyles = {
color: red,
backgroundColor: black,
padding: 2px
}
<p style={paragraphStyles}> inline styles applied here </p>

Compiled output:

<p style="color: red; background-color: black;">
inline styles applied here </p>

But with styled-components…

import styled from 'styled-components';
const Text = styled.div`
color: red,
background: black
`
<Text>Styled with CSS-in-JS </Text>

Compiled output:

<style>
.hash12345tf {
background-color: black;
color: red;
}
</style>
<p class="hash12345tf">Styled with CSS-in-JS</p>

See how styled-components attached a style tag on top of the DOM, while an inline style just works with the properties of the DOM node instead.

styled-components offers React Native mobile support

For teams with a React codebase who also use React Native for mobile development, styled-components is one of the best unified solutions out there for you. If consistency across platforms is a priority, then you’ll be glad to know that styled-components can be bundled into React Native.

Using styled-components in React Native, you can just assign alias names to comments, making your JSX code very legible. Also, you can convert any component, even custom components, to a styled component by simply invoking styled().

Scoped styles

In the frontend tooling world, the team at Vue was (in my opinion) the very first to perfect this concept of scoping styles. There is one very annoying thing about using CSS, and that is the fact that for a non-expert CSS user, it gets incredibly frustrating when you change the style of a particular element or class in your stylesheet and it inversely affects another seemingly unrelated element or behavior in the DOM. This is a great reason to use styled-components, as it is component-based and scoped, like Vue.

No-class policy in styled-components

styled-components enforces the use of props in the place of classes. This no-class policy has helped them make more developers follow best practices for controlling the behavior of a component.

Initially, you would write:

<h2 className="title primary">Hello World</h2> 
h2.Subtitle{
  font-size: 2em;
  color: green;
  
  &.primary{
    color: red;
  }
}

But now, it should be like this:

const Subtitle = styled.h2`
  font-size: 2em;
  color: ${props => props.primary ? 'red' : 'green'};
`;
<Subtitle primary>Hello World</Subtitle>

Notice how we have managed to keep HTML and CSS manipulations out of the component.

Alternatively, you can always go right back to className, and the same results will be achieved.

const Subtitle = styled.h2`
  font-size: 2em;
  color: green;
  
  &.primary{
    color: red;
  }
`;
<Subtitle className="primary">Hello World</Subtitle>

Server-side rendering

styled-components supports concurrent server-side rendering with stylesheet rehydration. The basic idea is that every time you render your app on the server, you can create a ServerStyleSheet and add a provider to your React tree that accepts styles via a context API.

This doesn’t interfere with global styles, such as keyframes or createGlobalStyle, and it allows you to use styled-components with React DOM’s various SSR APIs.

CSS unit and snapshot testing with Jest

Owing to the fact that styled-components is indeed made of components, you can unit test them. This is a major CSS breakthrough, and there is already a Jest integration support by the styled-component team.

Jest Styled Components is a set of utilities for testing styled-components with Jest. This package improves the snapshot testing experience and provides a brand new matcher to make expectations on the style rules. It can be installed like this:

npm install --dev jest-styled-components

Here’s an example of a test:

import React from 'react'
import styled from 'styled-components'
import renderer from 'react-test-renderer'
import 'jest-styled-components'
const Button = styled.button`
  color: red;
`
test('it works', () => {
  const tree = renderer.create(<Button />).toJSON()
  expect(tree).toMatchSnapshot()
})

And here’s an example of the resulting snapshot:

exports[`it works 1`] = `
.c0 {
  color: green;
}
<button
  className="c0"
/>
`

Sass and polished support

If you followed this article to this point, you must have noticed some nested styles, Sass, and even Polished, a toolset created by the team to further stretch the powers of Sass:

const Link = styled.a`
  cursor: pointer;
  text-decoration: none;
  &:hover {
    color: blue;
    text-decoration: underline;
  }
`;

Supporting Sass exposes the core mission of styled-components: to create the perfect CSS-in-JS experience without losing touch with everything we already love about CSS, including reducing the lines of code and other optimization features of Sass.

Arguments against using styled-components

It’s hard for me to come up with reasons not to use styled-components (especially given the title of the post), but it would be unfair if I did not also point out some (valid) concerns about CSS-in-JS frameworks in this article.

The JavaScript, React, and styled-components lock-in

There is a kind of nested lock-in that exists for every user of styled-components, and you should be aware and comfortable with it. You are locked into JavaScript, then into the React library, then finally into styled-components. If any of them goes away, you would have to painfully refactor your codebase.

Learning curve

Some people also indicate the learning curve of styled-components is steep, as well as the unique differences among CSS-in-JS frameworks. I would strongly recommend using and sticking to styled-components.

Continuity concerns

Styled-components started in 2017, and React developers always ask, “What if it stops being supported?” You have to make sure you are aware of this before using them in production.

Personal preferences

People do not like change. This is, in fact, a valid argument as CSS in a separate document is still one of the longest-lasting standards in web development.

Community concerns

Some people feel that the styled-components community is small and they might not get enough support as fast as they need it when they run into difficult bugs, use cases, or errors. This is also valid, but you have to consider the lock-in nature of styled-components.

Performance

The truth is if you are not using native CSS inline styles, there is a chance of having some performance overhead with any library you choose to use for styling. However, the little performance overhead you get is the price you pay for the power and flexibility you get from styled-components. The good thing is that styled-components is focused on improving the library’s performance on every new release. It keeps getting better.

Conclusion

There is a massively growing community around styled-components with over 33,000 ⭐️on GitHub, mostly coming from React developers, which is very encouraging and speaks to the prospects of longevity.

It is also very regularly maintained, you can check out the releases page here. If you are a CSS enthusiast, you can check out this State of CSS Survey that is currently all over the internet. Happy coding!