Building Cross-Platform Component Libraries for Web and Native with React

This ad is not shown to multipass and full ticket holders
React Summit US
React Summit US 2025
November 18 - 21, 2025
New York, US & Online
The biggest React conference in the US
Learn More
In partnership with Focus Reactive
Upcoming event
React Summit US 2025
React Summit US 2025
November 18 - 21, 2025. New York, US & Online
Learn more
Bookmark
Rate this content

Building products for multiple platforms such as web and mobile often requires separate code-based despite most of the components being identical in look and feel. Is there a way where we could use shared React component library on different platforms and save time? In this presentation I'll demonstrate one way to build truly cross-platform component library with a unique approach of using React & React Native in combination.

This talk has been presented at React Advanced 2021, check out the latest edition of this React Conference.

FAQ

Perttu Lähtenalahti is a professional who specializes in building cross-platform component libraries for React and React Native. He is originally from Finland and currently resides in Helsinki.

The main focus of Perttu Lähtenalahti's presentation is on building cross-platform components that can be used in both React and React Native projects, aiming for a single code base and maximum code reuse between platforms.

The slides for Perttu Lähtenalahti's presentation can be found on his website, perttu.dev, along with other resources and projects related to cross-platform component development.

Styled components are a CSS-in-JS solution that allows developers to write CSS code in JavaScript. This method is used by Perttu to style cross-platform components easily, ensuring consistency across web and native platforms.

Storybook is a tool for building UI components and pages in isolation. It helps developers visualize components independently from the application. Perttu uses separate Storybook instances for web and React Native to demonstrate components in different environments.

The challenge was to build a new feature that would work seamlessly across three React Native apps and one web app, maintaining a unified user experience and a single codebase, despite the platform differences.

Perttu's project involved an existing large React web app, making it impractical to integrate React Native Web without overhauling the entire system. Additionally, specific HTML tags like H1, H2, H3 were needed for SEO benefits, which required proper HTML rendering.

In React Native, platform-specific extensions like .ios or .android before the .js extension allow the React Native Bundler to automatically identify and use the correct component for each platform. Perttu also mentions a .native extension to differentiate components used in web apps from those in native apps.

Perttu Lähteenlahti
Perttu Lähteenlahti
21 min
25 Oct, 2021

Comments

Sign in or register to post your comment.
Video Summary and Transcription
This Talk discusses building cross-platform component libraries for React and React Native, based on a successful project with a large government-owned news organization. It covers the requirements for React Native knowledge, building cross-platform components, platform-specific components, styling, and the tools used. The Talk also highlights the challenges of implementing responsive design in React Native.

1. Introduction to Cross-Platform Component Libraries

Short description:

Today, I'm going to talk about building cross-platform component libraries for React and React Native. We will discuss the requirements for React Native knowledge, building cross-platform components, platform-specific components, styling, and the tools we'll use. This approach is based on a successful project with a large government-owned news organization.

Hello, everybody! My name is Perttu Lähtenalahti, and today I'm going to talk about how to build cross-platform component libraries for React and React Native. Before I dive into that subject, I just want to introduce myself briefly. My name, as mentioned, is Perttu Lähtenalahti. Don't worry, it's a really difficult one. I had it wrong once even in my passport. The reason for the difficult name is because I'm originally from Finland, currently living in beautiful Helsinki, Finland.

I have a website, perttu.dev. You can find this presentation as an article there. And a bunch of other stuff as well. You can also find me on GitHub and Twitter using this handle here. And the slides for this presentation, you can find them at this address. You can also find this project there. Which will allow you to test it out and build your own components using the way I'm going to show you. So, yeah. Let's dive into the subject of today's talk.

So, what this is going to be about is, of course, how to build cross platform components so that you can actually use them in both React and React Native projects. My idea is that the requirements for React Native knowledge are going to be pretty slim. Just knowing the basics of difference between React Native and React is supposed to be enough in this case and I hope that's going to be it. And using React Native, we're going to look into how to actually use that to build cross platform components that we can use on both web and native, in this case iOS and Android, and also how to build these platform specific components so that we can have the same components but the code being different between these two platforms. The reason for this, we're going to talk more later about it, but the basic idea is that we want to have a single code base and share as much code as possible. Towards the end of the talk, I'm going to dive a little bit into the styling and the pros and cons of this approach that I'm going to show you. Then, a few additional points. We're not going to use React Native web, which I think I'm going to mention soon, and we're also going to use styled components and storybook. For those who haven't used styled components, it's a really awesome CSS in JS solution that allows us to style our cloche platform components really easily in this case. Storybook is just something that I'm now using to show the components in a separate context from building a real application. So, yeah. This project or this approach that I'm going to show you is actually based on a customer approach that I did a little bit of time ago. So, that customer, I can't mention the name, but it was a big government-owned news organization and they actually had three React native apps and one web app that was powered by React. Basically their main website. And they were serving, I'd say, cloche, maybe even over a million people every day, so the user amounts were huge.

2. Building a Unified Cross-Platform Feature

Short description:

My team was asked to build a new feature that would allow live content on their platform. They wanted a single codebase for all their different apps and platforms. The feature needed to work in all four projects and have a unified experience. Despite the tight schedule, we managed to deliver a good version.

And they asked, my team was asked to build a new feature that would allow live content on their platform. This would mean video, polls, chats, and of course, live, updated articles about different things. And there were a few requirements, so despite having these three or four different platforms, four different apps, they actually wanted a single codebase. So this feature that we would build as a separate component library, it would need to work in all of these four projects, which was quite the requirement. And it also needed to have a unified experience so that it looks and feels the same despite you using it on a different app, different native app, different web app, and so on. And the time schedule was also really tight, so I think they wanted to get an MVP out in less than three months or so, which for a company of their size was quite a big undertaking, but we managed to get a pretty good version out.

3. Introduction to Cross-Platform Components

Short description:

Now, some of you who have used React Native and perhaps even React Native Web are now at this point wondering that, okay, this seems like a really good option to use React Native. However, we actually didn't have that choice, so the reason why we didn't use React Native was multitude, but they came down to this. We could use the familiar components like view text and image that we are already familiar and the companies developers were familiar with using in their React Native apps. However, in our case, it was already an existing and a huge React app, so we couldn't just bundle in React Native there and get that working, but we were limited to having it so that we need to have React code working in React project, and we need to have React Native code working in React project. And also in case we were kind of limited also by this view text and image components because we needed proper HTML text like H1, H2, H3 to actually get all the SEO benefits. So yeah, without further, let's actually talk about how we're going to do this, how we're going to do cross platform components.

Now, some of you who have used React Native and perhaps even React Native Web are now at this point wondering that, okay, this seems like a really good option to use React Native. However, we actually didn't have that choice, so the reason why we didn't use React Native was multitude, but they came down to this. So, of course, there were the good things. We could use the familiar components like view text and image that we are already familiar and the companies developers were familiar with using in their React Native apps. And those are really easy to build for both web and native if you have a completely new React Native web project. However, in our case, it was already an existing and a huge React app, so we couldn't just bundle in React Native there and get that working, but we were limited to having it so that we need to have React code working in React project, and we need to have React Native code working in React project. And also in case we were kind of limited also by this view text and image components because we needed proper HTML text like H1, H2, H3 to actually get all the SEO benefits. So yeah, without further, let's actually talk about how we're going to do this, how we're going to do cross platform components.

4. Building Cross-Platform Components

Short description:

React Native has a feature where you can do platform-specific extensions for files. By using the .ios and .android extensions, React Native Bundler can automatically bundle the correct component for each platform. However, there's also the .native extension, which allows you to create components that work on both web and native platforms. This approach still requires separate components for each platform, so let's explore how to build true cross-platform components.

So there's actually this feature in React Native where you can actually do platform specific extensions for files. So those who have used React Native already know that if you have an iOS component or Android component or Vue, you can just put the .ios before the .js extension and React Native Bundler will automatically know which component to use and bundle in the JavaScript bundle for which platform. And it works really well. What most people I think miss most of the time, because when we did that, there wasn't that many mentions of this, is actually that there's also .native extension, which tells basically React that, okay, use this component in the web app and this one with the native, use it in the Android and iOS. The difference comes from that the other one is of course managed by Webpack for the web, and then Metro Bundler, the React native bundler for the .native. And using this, you can actually already create components that work on either or platforms. You can put them in a single repository and use that. But that doesn't actually allow you to build cross-platform components yet. There are still separate components in separate parts. But let's dive into actually looking into how to do this.

5. Building React Native Components

Short description:

This project is a basic React Native pipe template with source and utility folders. It includes two separate Storybook instances for web and React Native. The component for the basic button, called my button, is used by both the native and React sides. The custom tags used in this component are defined in the utils.tags file, which allows React to handle them as tag names. By using background-specific extensions, React knows which files belong to each platform.

So, going back to the editor, you can actually see that this project that I built, it's a basic React native pipe template. The only thing I've added there is the source folder with the components and the utilities folders. Other than that, I've also added two different storybook instances.

So, there's scripts for running storybook on web and then running storybook on React Native. And that was actually something you just saw here. So, if I can go back. This is the two separate storybook instances. You can see the basic button there and you can see the basic button on the mobile as well.

Now, if we go back to the code editor, we can actually see that let's open up the component for the basic button. In this case it's called my button. So, let's go to the my button file. And we can see that single file that is currently if we look into the .stories file, we can see that it's used by both the native and the React side. And the way that's possible is that my button is a component that consists of button opacity and paragraph.

Now, those aren't any traditional React native or React tags that you might be familiar with. But instead they're customly defined. And you can see they're imported from this utils.tags file. So, let's actually look into that. And we can probably get an idea how this works. So, let's first look at the tags file. That's really simple. It's just exporting variables like heading1 is equal string h1. And React actually is quite smart and can handle these as the tag names straightaway, which is really cool. And we also have the tags native. And as we mentioned before, if we have these background specific extensions, this means that React native and React know which one of these files goes to which one. So, if we look at the native one, we can see that we're first importing all these image text, touchable, highlighted, and opposite, and then we're assigning them the same names we have on the text side. So, we have the heading1, it's always a text component. And that actually allows us to build the thing. So, we're exporting these two components in the component and using them. And then when React takes this component, it checks what is pop opacity for React and what it is for React Native.

6. React Component Styling with React Native CSS

Short description:

React takes the component and checks the opacity for React and React Native. It's simple, but it works well. The styles for the buttons are slightly different, but they function the same. The styled components allow for easy cross-platform styling using React Native CSS.

And then when React takes this component, it checks what is pop opacity for React and what it is for React Native. And that works. This is almost stupidly simple. But it works really well. As I mentioned, we've been running this in production for millions of people.

Next you might be wondering, how do I actually so, if we go back, let's look at the components. So, let's open the style button. And on the React Native side, we can see there is a blue button. On the React side, we can see there is a blue button as well. The styles are a little bit different. React Native has a flex one by default. So, it takes all the available space. But they still work the same way. So, they don't do anything. But they are clickable.

So, then let's look at the code behind that. And this is actually where the style components comes into play. Let's open my style button. We can see the style button is okay. It's very similar to my button from the previously. It has the button element and the button text. But actually, those components are not the same that we imported from the text. But instead they're here below. And using the styled constructor, we're passing the button opacity and the paragraph element, the styled constructor, and then adding styles. And that styles the component. So, this way you can actually style cross platform really easily. It works on both. The styled components uses React Native CSS, if I remember right, to actually turn the same CSS styles for the different platforms. And I think that's pretty cool.

7. Handling Button Clicks in React Native

Short description:

We have a similar codebase for two different platforms. To make a button clickable in React Native, we use the 'onPress' event instead of 'onClick'. We do a platform check and apply the correct prop, 'onPress' for React Native and 'onClick' for React. Handling mismatched prop names between React and React Native can be done with helper functions or TypeScript hacking.

And I think that's pretty cool. We're still having we have similar code base, but on two different platforms. Now, then how about if we actually want to do something with the button? So, we want it to be clickable. So, if we go back to the storybook, we can see that there's a working button in both. And what that actually does is it works, but doesn't really do much. When you click it, it actually logs to a console that pressed. So, let's look at the code behind here. Because this is where we actually will start to see where you have to start to do certain things to still be able to work with a singular component. So, let's open up the working button and we can actually see that there's the on press event that then does the console block pressed. And it's actually being called. I don't have the command line open, or available for looking, but I can verify that it does show up, the press text. And this is actually what enables that. So, what's happening here is, because on React side, when we're using normal DOM elements, every element is clickable because you use them mainly through mouse. But on React Native, because it's always, well, I'd say, almost always a touch screen, it's called an on press event there. And if we actually just put on press here, it will complain because you will expect that the button is an HTML element button. And if we put on click, it might actually complain that you don't have the on press event and on click event doesn't exist on React Native. So, we actually have to do this kind of platform check that, okay, platform, that's exported from YouTube platform. It basically just exports a constant variable on which platform it is. It's a Native for Native and web for web. And we do a check here, okay, which one it is. And we apply the correct prop, whether that is on click or on press for React and React Native. And these kind of things can get a little bit complicated if you have, like, mismatch between prop names between React and React Native. You could easily do a handler for these or, like, a helper function to allow you to build these more easily. In this case, or you could just do TypeScript hacking a little. That would probably help work as well. In this case, I just wanted to know how, wanted to show you how it works, like, under the hood. So it's not the cleanest, but you're still working in a single file, it's pretty easy to keep check up, to actually understand even this conditional code and conditional props.

8. Implementing the Web View Component

Short description:

Now let's explore a case where the implementation details between platforms vary significantly. We'll focus on the web view component, which opens React Advanced in a small iframe for the web version and uses a React Native web view component for the React Native version. Despite being two different components, the web view.stories file automatically determines which one to import based on the platform. This approach is simple, easy, and more maintainable than having separate code bases or adding React Native web to a React project.

Okay. So, yeah, now we have, now we've shown how to do actually functioning components, how to style them so that they're still the same file but served from two completely different platforms. How about in a case where we have a component that is actually the implementation details between the platforms varies a lot? Well, let's actually take a look at, so let's go back to the storybook and we can see here that we have the web view component and we open up that, it opens React Advanced in a small iframe and the same goes actually for the React Native app. But this is not an iframe, because React Native doesn't have support for iframe. This is actually a component called React Native web view that we're then just wrapping and assigning the URL as a prop. So let's look at the code a little more. Let's open up the web view component here and we can actually see straight away that webview.native and webview.dsx are two separate files. So that tells us that okay there's a difference between the implementation between the two platforms. On the native side, we can see that that's actually a container. Well that's just a wrapper that we imported from tax. And then we have errand webview which we see that is actually a webview imported as an errand webview from the package called React Native WebView. This allows us to use a webview on our React Native app. However, because React Native webview is, as the name tells, it only works on React Native. We have to have a separate kind of implementation for the web version. So, there you can see that the webview component is such an iframe. And despite these being two different components, the webview.stories automatically knows which one to import. And this would also work if you used it in a real React or React Native version. It would automatically know which component should we use. And hopefully this you're finally getting the idea of how this actually works. It's really simple. Really easy. And in my opinion, way more maintainable than using for example having two separate code bases or adding React Native web to a React project. So, yeah.

9. Challenges with Responsive Design in React Native

Short description:

React Native doesn't support responsive design tags like viewport, so you have to manually monitor the viewport size and change the styles accordingly. You can either use a helper function to apply responsive design tags based on the context or separate the components into different files.

Then let's talk about a little bit why this isn't the perfect solution. So, you might have already noticed that there were no responsive design things. The I frame, for example, on the web didn't take the full page or anything or it wasn't matched. The same goes with the buttons. They were just automatically that width. That's partly because doing actually responsive design in with style components is really easy. The problem is that React Native doesn't support those same responsive design tags like viewport and so on. Instead, there you have to monitor the viewport size manually through the JavaScript bridge. And then change the styles based on that. So, usually in those cases, you either have two options. You either make a helper function to detect in the styles whether you're using whether the component is being used on that context or native context and you apply the responsive design tags based on that. Or you do a complete JavaScript-based solution. Or then third, you separate those two components into two different files. That also works.

Check out more articles and videos

We constantly think of articles and videos that might spark Git people interest / skill us up or help building a stellar career

A Guide to React Rendering Behavior
React Advanced 2022React Advanced 2022
25 min
A Guide to React Rendering Behavior
Top Content
This transcription provides a brief guide to React rendering behavior. It explains the process of rendering, comparing new and old elements, and the importance of pure rendering without side effects. It also covers topics such as batching and double rendering, optimizing rendering and using context and Redux in React. Overall, it offers valuable insights for developers looking to understand and optimize React rendering.
Building Better Websites with Remix
React Summit Remote Edition 2021React Summit Remote Edition 2021
33 min
Building Better Websites with Remix
Top Content
Remix is a web framework built on React Router that focuses on web fundamentals, accessibility, performance, and flexibility. It delivers real HTML and SEO benefits, and allows for automatic updating of meta tags and styles. It provides features like login functionality, session management, and error handling. Remix is a server-rendered framework that can enhance sites with JavaScript but doesn't require it for basic functionality. It aims to create quality HTML-driven documents and is flexible for use with different web technologies and stacks.
React Compiler - Understanding Idiomatic React (React Forget)
React Advanced 2023React Advanced 2023
33 min
React Compiler - Understanding Idiomatic React (React Forget)
Top Content
Watch video: React Compiler - Understanding Idiomatic React (React Forget)
Joe Savona
Mofei Zhang
2 authors
The Talk discusses React Forget, a compiler built at Meta that aims to optimize client-side React development. It explores the use of memoization to improve performance and the vision of Forget to automatically determine dependencies at build time. Forget is named with an F-word pun and has the potential to optimize server builds and enable dead code elimination. The team plans to make Forget open-source and is focused on ensuring its quality before release.
Using useEffect Effectively
React Advanced 2022React Advanced 2022
30 min
Using useEffect Effectively
Top Content
Today's Talk explores the use of the useEffect hook in React development, covering topics such as fetching data, handling race conditions and cleanup, and optimizing performance. It also discusses the correct use of useEffect in React 18, the distinction between Activity Effects and Action Effects, and the potential misuse of useEffect. The Talk highlights the benefits of using useQuery or SWR for data fetching, the problems with using useEffect for initializing global singletons, and the use of state machines for handling effects. The speaker also recommends exploring the beta React docs and using tools like the stately.ai editor for visualizing state machines.
Routing in React 18 and Beyond
React Summit 2022React Summit 2022
20 min
Routing in React 18 and Beyond
Top Content
Routing in React 18 brings a native app-like user experience and allows applications to transition between different environments. React Router and Next.js have different approaches to routing, with React Router using component-based routing and Next.js using file system-based routing. React server components provide the primitives to address the disadvantages of multipage applications while maintaining the same user experience. Improving navigation and routing in React involves including loading UI, pre-rendering parts of the screen, and using server components for more performant experiences. Next.js and Remix are moving towards a converging solution by combining component-based routing with file system routing.
Design Systems: Walking the Line Between Flexibility and Consistency
React Advanced 2021React Advanced 2021
47 min
Design Systems: Walking the Line Between Flexibility and Consistency
Top Content
The Talk discusses the balance between flexibility and consistency in design systems. It explores the API design of the ActionList component and the customization options it offers. The use of component-based APIs and composability is emphasized for flexibility and customization. The Talk also touches on the ActionMenu component and the concept of building for people. The Q&A session covers topics such as component inclusion in design systems, API complexity, and the decision between creating a custom design system or using a component library.

Workshops on related topic

React Performance Debugging Masterclass
React Summit 2023React Summit 2023
170 min
React Performance Debugging Masterclass
Top Content
Featured Workshop
Ivan Akulov
Ivan Akulov
Ivan’s first attempts at performance debugging were chaotic. He would see a slow interaction, try a random optimization, see that it didn't help, and keep trying other optimizations until he found the right one (or gave up).
Back then, Ivan didn’t know how to use performance devtools well. He would do a recording in Chrome DevTools or React Profiler, poke around it, try clicking random things, and then close it in frustration a few minutes later. Now, Ivan knows exactly where and what to look for. And in this workshop, Ivan will teach you that too.
Here’s how this is going to work. We’ll take a slow app → debug it (using tools like Chrome DevTools, React Profiler, and why-did-you-render) → pinpoint the bottleneck → and then repeat, several times more. We won’t talk about the solutions (in 90% of the cases, it’s just the ol’ regular useMemo() or memo()). But we’ll talk about everything that comes before – and learn how to analyze any React performance problem, step by step.
(Note: This workshop is best suited for engineers who are already familiar with how useMemo() and memo() work – but want to get better at using the performance tools around React. Also, we’ll be covering interaction performance, not load speed, so you won’t hear a word about Lighthouse 🤐)
Next.js for React.js Developers
React Day Berlin 2023React Day Berlin 2023
157 min
Next.js for React.js Developers
Top Content
Featured WorkshopFree
Adrian Hajdin
Adrian Hajdin
In this advanced Next.js workshop, we will delve into key concepts and techniques that empower React.js developers to harness the full potential of Next.js. We will explore advanced topics and hands-on practices, equipping you with the skills needed to build high-performance web applications and make informed architectural decisions.
By the end of this workshop, you will be able to:1. Understand the benefits of React Server Components and their role in building interactive, server-rendered React applications.2. Differentiate between Edge and Node.js runtime in Next.js and know when to use each based on your project's requirements.3. Explore advanced Server-Side Rendering (SSR) techniques, including streaming, parallel vs. sequential fetching, and data synchronization.4. Implement caching strategies for enhanced performance and reduced server load in Next.js applications.5. Utilize React Actions to handle complex server mutation.6. Optimize your Next.js applications for SEO, social sharing, and overall performance to improve discoverability and user engagement.
Concurrent Rendering Adventures in React 18
React Advanced 2021React Advanced 2021
132 min
Concurrent Rendering Adventures in React 18
Top Content
Featured Workshop
Maurice de Beijer
Maurice de Beijer
With the release of React 18 we finally get the long awaited concurrent rendering. But how is that going to affect your application? What are the benefits of concurrent rendering in React? What do you need to do to switch to concurrent rendering when you upgrade to React 18? And what if you don’t want or can’t use concurrent rendering yet?

There are some behavior changes you need to be aware of! In this workshop we will cover all of those subjects and more.

Join me with your laptop in this interactive workshop. You will see how easy it is to switch to concurrent rendering in your React application. You will learn all about concurrent rendering, SuspenseList, the startTransition API and more.
React Hooks Tips Only the Pros Know
React Summit Remote Edition 2021React Summit Remote Edition 2021
177 min
React Hooks Tips Only the Pros Know
Top Content
Featured Workshop
Maurice de Beijer
Maurice de Beijer
The addition of the hooks API to React was quite a major change. Before hooks most components had to be class based. Now, with hooks, these are often much simpler functional components. Hooks can be really simple to use. Almost deceptively simple. Because there are still plenty of ways you can mess up with hooks. And it often turns out there are many ways where you can improve your components a better understanding of how each React hook can be used.You will learn all about the pros and cons of the various hooks. You will learn when to use useState() versus useReducer(). We will look at using useContext() efficiently. You will see when to use useLayoutEffect() and when useEffect() is better.
Introducing FlashList: Let's build a performant React Native list all together
React Advanced 2022React Advanced 2022
81 min
Introducing FlashList: Let's build a performant React Native list all together
Top Content
Featured Workshop
David Cortés Fulla
Marek Fořt
Talha Naqvi
3 authors
In this workshop you’ll learn why we created FlashList at Shopify and how you can use it in your code today. We will show you how to take a list that is not performant in FlatList and make it performant using FlashList with minimum effort. We will use tools like Flipper, our own benchmarking code, and teach you how the FlashList API can cover more complex use cases and still keep a top-notch performance.You will know:- Quick presentation about what FlashList, why we built, etc.- Migrating from FlatList to FlashList- Teaching how to write a performant list- Utilizing the tools provided by FlashList library (mainly the useBenchmark hook)- Using the Flipper plugins (flame graph, our lists profiler, UI & JS FPS profiler, etc.)- Optimizing performance of FlashList by using more advanced props like `getType`- 5-6 sample tasks where we’ll uncover and fix issues together- Q&A with Shopify team
React, TypeScript, and TDD
React Advanced 2021React Advanced 2021
174 min
React, TypeScript, and TDD
Top Content
Featured Workshop
Paul Everitt
Paul Everitt
ReactJS is wildly popular and thus wildly supported. TypeScript is increasingly popular, and thus increasingly supported.

The two together? Not as much. Given that they both change quickly, it's hard to find accurate learning materials.

React+TypeScript, with JetBrains IDEs? That three-part combination is the topic of this series. We'll show a little about a lot. Meaning, the key steps to getting productive, in the IDE, for React projects using TypeScript. Along the way we'll show test-driven development and emphasize tips-and-tricks in the IDE.