How to Split Your UI into React Components: Finding the Right Balance

In React development, components are the fundamental building blocks of a user interface. But a common challenge is deciding how to split the UI: should you create one large component that handles everything? Or break the UI down into dozens of small ones? This article explains the trade-offs, common pitfalls, and four practical criteria for finding the right balance.

The Problem: Big vs. Small Components

When building components, it’s easy to go too far in either direction. Both approaches come with their own set of challenges.

The Pitfalls of Big Components

Creating large components might seem simpler initially because it handles everything in one place, but it can lead to several problems down the line:

• Too Many Responsibilities: Similar to functions in clean code principles, a component should ideally have a single responsibility. Learn more about the Single Responsibility Principle.
  A large component tends to handle multiple functionalities, making it harder to understand, test, and debug if an error arises.

• Excessive Props: As the complexity of a component grows, so does the number of props it might require. Passing numerous props down through the component tree can become error-prone.

• Low reusability: The bigger the component, the harder it is to reuse parts of it elsewhere.

• Hard to maintain and understand: When a component does too much, its codebase becomes lengthy, making it harder for developers to understand and maintain.

The Downsides of Too-Small Components

On the other end, breaking everything into tiny pieces can also introduce complexities:

• Over-Abstraction: Abstracting too much too early can result in unnecessary indirection, making it harder to trace the flow of data and logic. Learn more about Abstraction.

• Confusing Codebase: Having hundreds of tiny components can lead to a confusing codebase, where the relationships between the components become difficult to grasp.

• Harder debugging: You spend more time jumping between files than writing features.

• Performance Overhead: While React is efficient, an excessive number of components can potentially lead to a slight performance overhead due to the increased number of virtual DOM comparisons.

The key takeaway is that we need to find the right balance between creating few large components and too many small ones.

Finding the Sweet Spot: Criteria for Splitting UI into Components

The right balance is splitting your UI into components that are large enough to be useful but small enough to be maintainable.

This balance ensures your UI is:

• Easy to understand

• Reusable where needed

• Scalable as your app grows

Here are four key criteria to guide your decision-making process:

1. Logical Separation of Content or Layout

Consider if a section of the UI contains elements that are conceptually or visually separate from others.

Ask yourself:

• Does this part of the UI contain content or layout that doesn’t belong together?

• Can I separate it logically into smaller chunks?

If yes, it should be its own component. For example, in a blog post page, the header, content body, and comments section naturally deserve their own components.

2. Reusability

Identify parts of your UI that are or could potentially be reused in different areas of your application. Extracting these reusable sections into their own components promotes a more DRY (Don't Repeat Yourself) codebase.

Ask yourself:

• Will I need this element in multiple places?

• Do I want it to be easily reused in the future?

If yes, it should be its own component. For example, a button or input field reused across forms should be a standalone component.
If you find yourself copying and pasting similar JSX structures, that's a strong indication that a reusable component is needed.

3. Responsibilities and Complexity

Evaluate the responsibilities of a particular section of your UI.

Ask yourself:

• Is this component doing too many things at once?

• Does it rely on too many props, states, or effects?

• Is it becoming difficult to read or test?

If yes, break it down. For example, a dashboard component that fetches data, renders charts, handles filters, and manages pagination should be split into smaller pieces.

4. Personal Style

Finally, style plays a role. Some developers prefer slightly larger components for readability, while others prefer smaller, tightly scoped ones. The key is consistency across your codebase.

For example, some teams wrap form inputs into their own FormInput components, while others leave them inline. Both can work as long as the team agrees.

Conclusion

Effectively splitting your UI into React components is a crucial skill for building scalable and maintainable applications. Remember:

• Too big means: hard to maintain, low reusability.

• Too small means: confusing, over-abstracted.

• Balanced means: easier to maintain, test, and reuse.

By understanding these criteria, you can avoid common pitfalls and create a codebase that is easier to maintain, test, and reuse as your application grows. Remember that breaking your UI into components is an iterative process, so you may need to refactor as your application evolves.