Leveraging the Compound Components Pattern in React for scalable and flexible UI

Hey there, Nik here! I’m excited to kick off a series of blog posts that dive deep into the world of front-end development.

Alright, so here’s the deal for today's post: building reusable, scalable, and flexible components in front-end development is like trying to build a LEGO set that works for every kid out there. You want it to be fun, sturdy, and adaptable enough that it can be put together in different ways without falling apart (or stepping on it by accident!).

When it comes to React, there’s a nifty trick called the Compound Components Pattern that lets us create customisable, self-contained components. These little guys are like puzzle pieces you can snap together however you want, but without leaving random pieces all over the floor… well, usually.

In this article, we’ll dive into what makes this pattern useful, where it shines (and where it doesn’t), and how we can use it to build some seriously flexible layouts. So, if you’re into making React components that play well with others, stick around—you’re in for a treat (or at least fewer headaches)!

What is compound components pattern?

In the early days of UI development, developers were just happy to make things work without breaking (too much). But as applications grew, our components started behaving like rebellious teenagers—doing their own thing, refusing to talk to each other, and causing chaos across the app. So, developers started looking for ways to get related components to “play nice” together, especially in more complex UIs.

Enter the compound components pattern!

This pattern, popularised by React, brings together groups of related components to act like a close-knit family within a single parent component (think of it as family game night, but with less yelling). Instead of throwing multiple independent components into the wild, compound components give us a single entry point, where each “child” component (or subcomponent) behaves according to the parent’s rules—kind of like siblings sharing one Wi-Fi password.

The cool part? The parent component takes charge of shared state and context, so the children don’t have to worry about managing their own state or behaviour. They communicate implicitly with the parent, meaning they don’t have to constantly pass notes back and forth (or, in developer terms, props). It’s all about streamlining the component ecosystem, making it especially effective for building complex and interdependent UI structures.

Further below, I’ll show how this pattern works in real life with a CMS layout feature for banners. Here, a CmsBanner component will act as the entry point, with CmsBlock as its loyal sidekick. CmsBlock will house our Title and Description components, keeping our layout clean, organised, and easy to maintain. So let’s dive in and see this pattern in action - it’s like family therapy for your components, but without the therapist’s bill.

What are some of the pros of applying the compound components pattern in our apps?

So, what’s in it for us if we use this pattern? Why go through the trouble of organising our components into one big family? Let’s break down the perks:

1. Encapsulates Complexity:
   Imagine trying to organise a party where everyone just shows up and does whatever they want. Chaos, right? Compound components are like setting up themed stations at that party, where each group knows exactly what to do. With compound components, we can build complex UIs with tons of options and child components without making each component figure out what the others are doing. This keeps everything modular and the API nice and clean - no guessing games required!

2. Improved Flexibility and Composition:
   This pattern is all about letting us mix and match! Picture CmsBanner as the main component - a head honcho of sorts letting you add any combination of CmsBlock instances, with titles, descriptions, images, or whatever you need, in any order. So you’re free to rearrange elements as needed, all without breaking a sweat (or the component).
   Simplifies State Management and Context Sharing: Think of compound components as that one super-organised friend who just handles all the logistics for everyone. With the parent managing the state and context, the child components get to relax where they don’t have to worry about managing their own states and can just focus on doing their thing. This keeps child components nice and simple, and it makes testing and troubleshooting way easier (fewer moving parts mean fewer bugs).

3. Increased Developer Experience:
   Talking from experience developers are happy when things just… work, right? This pattern keeps the component API intuitive and consistent, so there’s less head-scratching. With the main component “handing out” the subcomponents in a clear, structured way, devs don’t have to spend ages figuring out how to use them. The result? Faster development, a smoother learning curve, and a lot more time for coffee.

In short, using compound components gives us a toolbox that’s organised, flexible, and (dare I say) a bit fun to work with. And if it saves us some troubleshooting time, I’d say that’s a win all around!

What are some of the cons of applying the Compound Components Pattern in our apps?

Alright, so now that we’ve sung its praises, let’s talk about where the Compound Components Pattern might give us a little grief. Because, like anything that looks too good to be true, there are a few catches:

1. Increased Complexity in Prop Drilling:
   While it’s great to have the parent handle the state, compound components still have to pass down a lot of props. And let’s be honest: keeping track of all those props can start feeling like one of those “Choose Your Own Adventure” books (except, you know, without the adventure). If your component hierarchy starts getting taller than a skyscraper, it’s easy to lose track of which props are meant for which subcomponent. So, this can mean some extra effort to stay organised.

2. Code Splitting Challenges:
   Code splitting can be tricky with compound components because they usually travel together like a package deal. So if your CmsBanner only needs Title and not Description, you might still end up importing the whole crew. This can impact your bundle size, especially if you’re not reusing these subcomponents all over the app (obviously exaggerating here for illustration purposes). In short, if you’re looking to trim down the bundle, compound components may sometimes work against you.

3. Potential for Over-Encapsulation:
   If you make your compound components too encapsulated, they can become tough to use outside of the very specific structure you designed. It’s like building a LEGO set that can’t be taken apart - you lose flexibility if requirements change, or if you want to reuse parts of the component in other places. So, it’s essential to strike the right balance, or you’ll end up with components that feel too boxed-in.

But hey, enough with the theory - let’s get to the fun part and see how compound components bring modularity and flexibility to life!

Compound Components Pattern in action

I'll break down each part of this pattern and explain how these components work together to create a clean, organised layout.

Title.tsx

Our Title component handles the job of a header, and it’s versatile enough to be anything from an h1 to an h4 - just tell it what it should be by setting the as prop. Plus, it comes with some style presets to keep your headings looking sharp.

Here, the Title component is equipped with customisable alignment, making it flexible for various layouts. You simply pass in which heading level you want (as='h1', as='h2', etc.), and the styling will take care of the rest. This approach ensures that all headings within our layout follow a consistent style.

CmsBlock.tsx

Next, we have CmsBlock, which is like a mini canvas. It’s a container component that can be sized according to the layout’s needs. Here, you can include elements like Title and Description as its properties, giving you a powerful, reusable structure for building your app’s content blocks.

With CmsBlock, we’re keeping it easy for the user. Since Title and Description are properties of CmsBlock, there’s no need for separate imports. You can think of it as a mini app-builder for content blocks - pick your block, size it, and you’re good to go. This also means you get a tidy layout where everything you need is accessible from CmsBlock.

CmsBanner.tsx

At the top of the hierarchy is CmsBanner, the ultimate layout boss! It wraps around all CmsBlock components and gives each one structure and styling. CmsBanner can be sized as "small", "medium", or "large", setting up a neat modular layout with consistent styling and spacing.

Here, CmsBanner acts as the main layout component, letting you plug-in multiple CmsBlock elements. You get all the benefits of a consistent style, but with the freedom to rearrange and resize blocks as needed.

Usage Example

And here’s how all of these components come together in an example:

In this example, we’re using CmsBanner as the layout foundation and adding CmsBlock components for each part of the content. Each CmsBlock includes a Title, and you can also easily include images or other elements to create a professional, flexible layout. This setup keeps your code organised and declarative, making it easy to see what’s going on without diving too deep.

So, there you have it! This pattern lets us build well-structured layouts that are easy to work with and extend. And best of all, it’s all done with the simplicity and power of compound components.

Conclusion

The Compound Components Pattern is like having a toolkit that just “gets” how we want to build complex UIs in React. It gives us this flexible, modular way to design components that feel natural to use and compose, without all the usual setup overhead. By grouping related components under one parent, we let them work together seamlessly, simplifying what could otherwise be a tangle of state and props management.

Sure, there are a few quirks. Sometimes, dealing with props flowing down from the parent can feel like playing telephone if the component hierarchy gets too deep. And, yes, the bundle size might get a bit hefty if we aren’t careful about how much we’re importing all at once. But honestly, with a little planning, these are easy enough to work around. Over-encapsulation can also happen if we go a bit overboard, but by defining clear use cases, we can keep things manageable.

The real magic of this pattern is in the development flow it creates. It lets us build reusable, intuitive UIs that other developers can pick up quickly no scavenger hunt for where different states or props are coming from. This means less back-and-forth, a more unified API, and faster development cycles. In a fast-moving project or team environment, that’s a huge win!

In the end, while this pattern might not be the answer for every single component, it’s an incredibly useful option to have in our React toolbox. For building UIs that are robust, flexible, and a joy to work with, compound components can make a real difference. Give it a try, and see how it transforms your workflow and who knows, it might just become one of your go to patterns!

As always, your recommendations and feedback are welcomed! I hope you found this exploration of the Compound Components pattern insightful and enjoyable. Happy coding!