Emotion vs Styled Components

31 August 2023

Emotion vs Styled Components

Irelia Codeheart, Senior Developer

Comparative Analysis of Features and Functionality

Understanding the Features of Styled Components

Styled-components is one of the most popular CSS-in-JS libraries which focuses on enhancing the developers' experience and providing unique ways to style your components. One significant feature is the ability to use props in your component styles, allowing for dynamic changes in rendered tags without the need to call any JavaScript logic operations. This feature provides a high level of component reusability.

In terms of syntax, styled-components favor a more traditional CSS-like styling syntax. Here's a simple example:

const StyledButton = styled.button`
    color: ${props => props.primary ? "white" : "palevioletred"};
    background-color: ${props => props.primary ? "palevioletred" : "white"};

Styled-components also support theming, allowing for consistent design across your app.

Exploring the Capabilities of Emotion

Emotion, on the other hand, provides a flexible and performant alternative for CSS-in-JS. It offers a developer-friendly approach with various ways to style your components. Emotion supports both string and object styles, further enhancing its flexibility:

const { css } = require('@emotion/core')

const dynamicStyle = props => css`
  color: ${props.color};

render(<div css={dynamicStyle({ color: 'hotpink' })}>This is hotpink.</div>)

Emotion is faster than styled-components, ready for React Concurrent mode, and has a smaller bundle size. This results in better performance and faster load times. Moreover, Emotion supports out-of-the-box server-side rendering, labelling, and important selectors.

Common Functionalities and Differences

Both libraries provide similar functionalities including auto-prefixing, elimination of unused styles, and ensuring isolation of styles. These features ensure your styles, are efficient, prevent styles leakage and ensure compatibility with different browsers.

However, there are notable differences between the two. Emotion tends to be more efficient in terms of performance while styled-components provide more unique and complex styling options. Emotion's smaller bundle size and better rendering performance offer a considerable advantage, especially for larger projects. On the other hand, styled-components are actively improving their performance and have their unique selling points including more readability and better debugging through self-generated component names.

Knowing these variations and capabilities of both libraries can help developers better decide depending on the specifications and requirements of their project. Both libraries offer significant advantages and the choice between the two will often depend on project requirements and personal preference.

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Performance Comparison: Styled Components vs Emotion

When choosing a CSS-in-JS library for your project, performance is a key parameter to consider. Discussed here are the specific areas: build size, rendering performance, and how increasing the number of styled components affects performance in both libraries.

Impact on Build Size

Larger build sizes can be a hindrance in page load times and affect user experience. Emotion seems to have an upper hand in this aspect. It generally results in a smaller bundle size compared to Styled Components, thereby aiding in better page load performance. However, it's important to note that the impact may vary based on factors like the complexity of code and use cases implemented.

Rendering Performance

Next, we look into rendering performance. While Styled Components is highly appreciated for its simplicity and unique styling options, it is slightly lagging behind Emotion in terms of speed. Emotion has been found to perform better in rendering, speeding up page interactivity times. However, there is an ongoing effort from Styled Components' contributors to enhance its performance, with claims of having reduced the gap to within 0.5-2x of Emotion.

When it comes to server-side rendering (SSR), both libraries create challenges on rendering performance, hence, developers need to opt for careful considerations based on their specific SSR needs.

How An Increasing Number of Styled Components Affects Performance

Lastly, as your project expands, you might wonder how an increasing number of Styled Components affects performance. The truth is, an increase in the number of styled components affects both libraries. However, with efficient coding practices and component structuring, these performance hits can be minimized.

On one hand, Styled Components maintain a constant rendering time despite the increase in component count but at the same time, it results in more JavaScript computation and a slight memory increase. Emotion, conversely, has more linear performance characteristics, i.e., an increase in component count could start to impact your rendering performance more compared to Styled Components but at a slower rate.

Remember both libraries have their own trade-offs and their performance is impacted based on project-specific needs, structure, and usage. Therefore, take into account these parameters before making a choice between Styled Components and Emotion for your project.

Real-World Use Cases and Examples

In this section, we're going to delve into real-world examples and use cases of Styled Components and Emotion. We'll see how these libraries can affect the quality of your code, productivity, and user experience.

Styling Applications with Styled Components: Practical Examples

Styled Components shines when it comes to encapsulating styles to independent components. It provides a neat, declarative way of writing CSS tied directly to individual components, improving maintainability and reusability. This library can have immense benefits in large-scale projects where the need for unique styles in different components is common.

Let's consider a sample code snippet of a button styled using Styled Components.

import styled from 'styled-components';
const Button = styled.button`
    background: papayawhip;
    color: palevioletred;
    font-size: 1em;
    padding: 0.25em 1em;
    border: 2px solid palevioletred;
    border-radius: 3px;
<Button>Click me !</Button>

In the above-styled component, we are using tagged template literals to create our Button component. The styles are linked directly to our components, making our button component self-contained and reusable across the application without style conflicts.

Using Emotion in Real-World Projects: Case Studies

Emotion, on the other hand, is great for projects that require highly dynamic themes with an intense amount of customization. It's also renowned for its smaller bundle size, boosting performance.

A compelling aspect of Emotion is the way it enables developers to directly write CSS in their JavaScript. This allows for dynamic styling based on props or the global theme - something that can be quite beneficial in various scenarios.

Here's an example of how you can style a div using Emotion.

/** @jsxImportSource @emotion/react */
import { css } from '@emotion/react`
const style = css`
    color: hotpink;
    font-size: 24px;
    &:hover {
        color: darkorchid;
<div css={style}>Hover to change color!</div>

In the above example, we use Emotion to create a style object. This css object will be processed by the Emotion's css function to generate a style string which then can be passed to the css prop of the div element.

Whether you choose Styled Components or Emotion depends on the specific needs of your project. However, both tools are fantastic for styling in a React.js environment.

Pros and Cons of Styled Components and Emotion

Developing a comprehensive understanding of the advantages and disadvantages of any tool is pivotal in making an informed decision about its utility. In line with this, the following section will delve into the pros and cons of Styled Components and Emotion based on real-world use cases and performance benchmarks.

Advantages of Styled Components

Styled Components has numerous strengths making it a popular choice among developers.

  • The Restyling feature enables the reusability of existing components with different styles, thereby promoting reusability.

  • The Theming functionality allows the provisioning of themes without passing props manually, a huge convenience.

  • With Styled Components, you can utilize CSS frameworks in your components seamlessly. It can also eliminate class name bugs as each CSS module gets a unique class.

  • Lastly, it has a larger community and ecosystem which can be beneficial in terms of support and resource availability.

const Button = styled.button`
  color: ${props => props.theme.primary};

Drawbacks of Styled Components

Despite the appealing features, Styled Components does exhibit some cons.

  • The library has a larger bundle size compared to Emotion, which can hamper load times.

  • Profiling and debugging can be challenging as component names often get replaced with class names in DevTools.

  • Performance is slightly lower compared to Emotion, especially in the case of server-side rendering.

Benefits of Using Emotion

Emotion has gained traction due to its beneficial features.

  • One key advantage is its small bundle size, contributing to better load times and overall performance.

  • Its developer-friendly approach enables you to write regular React components and work with object styles, increasing flexibility and productivity.

  • Emotion also supports the 'css' prop allowing for easier code composition and cleaner syntax.

/** @jsx jsx */
import { css, jsx } from '@emotion/core'

<div css={{ color: 'hotpink' }}>Some text</div>

Cons of Emotion

While Emotion has many additions and advantages over Styled Components, it comes with its share of drawbacks.

  • It has a smaller community, which may limit availability of resources and support.

  • Certain Emotion features, such as extracting critical CSS on the server, does require additional setup.

  • There are instances where Emotion might not be the best fit, especially if you're looking for more unique and complex styling options that Styled Components provides.

Having dissected the pros and cons of both Styled Components and Emotion, it is essential to understand that the choice between these libraries strictly depends on the requirements of your project and your personal preference.

Making the Right Choice: When to Use Styled Components or Emotion

The aim of this section is to help developers navigate the decision-making process when it comes to choosing between these two CSS-in-JS libraries: Styled Components and Emotion.

Considerations for Choosing Between Styled Components and Emotion

Before selecting a library for a project, it's crucial to evaluate specific aspects such as build size, load time, runtime speed, components restyling, theming options, and developer-friendliness. These all play a crucial role in the overall performance and usability of the library.

From the aspect of build size and loading time, Emotion tends to outperform Styled Components, offering a smaller build size and faster loading times. With runtime speed, Emotion also showcased better performance in tests done in March 2019, indicating a faster rendering speed.

On the other hands, Styled Components presents a unique advantage when it comes to restyling existing components and theming. Its flexibility and compatibility with CSS frameworks make it a preferred choice for projects that demand complex and unique styling. It also boasts a larger community, which often indicates more comprehensive resources for learning and troubleshooting.

Meanwhile, Emotion has been praised for its developer-friendliness. Its css prop feature can potentially reduce the need for additional libraries and offers a flexible way to write styles in JavaScript.

/**Using Emotion CSS prop**/
const Component = () => <div css={{ color: 'hotpink' }} />

Impact of Project Requirements and Personal Preference

There is no definitive answer when choosing between Styled Components and Emotion as both libraries offer robust options for styling in React. However, project requirements and personal preference often tip the balance one way or the other.

For instance, if your project does not require heavy theming or complex CSS, then the better performance and smaller size of Emotion might be the more suitable choice. Alternatively, if you are working on a project that necessitates unique and complex styling, then the theming capabilities and ability to restyle existing components offered by Styled Components might be more beneficial.

In terms of personal preference, some developers appreciate Emotion's developer-friendliness and flexibility in writing styles. Others, on the other hand, might lean towards Styled Components due to its larger community and the resources available.

At the end of the day, the right choice will heavily depend on the specific requirements of your project and your personal preference as a developer.

/**Styled Components styling example**/
import styled from 'styled-components';

const Button = styled.button`
  background: ${props => props.primary ? 'palevioletred' : 'white'};
  color: ${props => props.primary ? 'white' : 'palevioletred'};

In conclusion, choosing a CSS-in-JS library requires balancing various factors such as performance, project requirements, and personal preferences. Both Styled Components and Emotion have their own strengths and limitations, making them suitable for different scenarios in real-world applications.

Step by Step Tutorial: Working with Styled Components and Emotion

As we reach the conclusion of our comprehensive guide, let's delve into a step-by-step tutorial to see Styled Components and Emotion in action. Along the way, we'll illustrate how these libraries can enhance your experience in building visually impressive and performant web interfaces.

Setting up a Project with Styled Components

First, we're going to walk through setting up a sample project with Styled Components:

# Initiate a new React project
npx create-react-app styled-components-demo
cd styled-components-demo

# Install Styled Components library
npm install styled-components

Once installed, you can import styled from 'styled-components' at the top of your JavaScript or TypeScript file. Now, you're ready to start designing your components!

Creating and Styling Components with Emotion

Let's do the same for Emotion:

# Initiate a new React Project
npx create-react-app emotion-demo
cd emotion-demo

# Install the required Emotion packages
npm install @emotion/react @emotion/styled

With Emotion installed, we can style our components directly by importing the styled function from '@emotion/styled' in our JS or TS file. A breeze, isn't it?

Hands-on Example: Building a Simple Web Page

Suppose you want to create a simple web page with a header and a few styled paragraphs. With either library, you can elegantly define these styles in your JS or TS file. Here's how you might do this with Styled Components:

import styled from 'styled-components';

const StyledHeader = styled.h1`
  color: blue;
  font-size: 2em;

const StyledParagraph = styled.p`
  color: gray;
  font-size: 1.5em;

// Then, in your render method:
    Welcome to our Styled Components tutorial!
    This paragraph is styled with Styled Components.

Now that we've walked through working with Styled Components and Emotion, it's clear they're both powerful tools for styling your React components, offering an insightful approach to creating compelling, reusable design systems.

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