CSS in JS in React

What is CSS in JS

CSS in JS is a popular way to style React applications. It involves writing styles in JavaScript and applying them directly to React components. This makes it easy to easily and efficiently style React components, as well as provide them with dynamic styling. Additionally, CSS in JS allows developers to use features such as variables, mixins, nesting, and media queries, making it easier to create complex and responsive applications. By using CSS in JS, developers can create a more consistent and efficient styling solution for their React applications.

When using CSS in JS in a React application, the styles are typically scoped to the individual components, which can lead to several benefits and drawbacks. In the next shows in this series, we will cover inline styling as well as the emotion library that are closely linked with CSS in JS.

Pros of CSS-in-JS for React apps:

1. Scoped styles: Because styles are scoped to the individual components, there is less likelihood of style collisions, where one style accidentally overrides another.
2. Dynamic styling: Because styles are defined in JavaScript, it's easy to use dynamic logic to compute styles based on props or state.
3. Dead code elimination: Using a CSS-in-JS library like styled-component, this allow to eliminate the unecessary styles that you are not using anymore.
4. Co-location of styles and components: Because styles are defined within the same file as the component, it can be easier to understand and modify the overall design of a component.

Cons of CSS-in-JS for React apps:

1. Learning curve: For developers who are not familiar with JavaScript-based styling, the transition to CSS-in-JS can be challenging.
2. Complexity: Because styles are defined in JavaScript, it can be more complex to debug and maintain.
3. Performance overhead: Some CSS-in-JS library create a new className for each component, leading to a high number of CSS class and increase the complexity of the stylesheets
4. Lack of browser support for some advanced CSS features: Some CSS-in-JS libraries don't support some advanced CSS features like media queries and keyframe animations, which can force you to fall back to CSS.

Conclusion

Ultimately, the decision to use CSS-in-JS in a React app will depend on the specific needs of the project, as well as the preferences of the development team. It can be helpful to weigh the pros and cons in relation to the particular requirements of the project before making a decision.

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