Find out the answer to “How does React Native work?” under the hood, how it differs from web development, and what you can do with it.
Suppose you are looking for a way to develop mobile applications that run on multiple platforms with a single codebase. In that case, you might have heard of React Native. This software framework has become a popular choice for developing mobile applications for both iOS and Android. But how does React Native work under the hood?
In this article, we will answer this question and more as we explore the inner workings of this software framework. You can also decide if it is the right tool for your next mobile development project.
What is React Native?
This is a popular open-source framework for building cross-platform mobile applications created by Facebook in 2015. Although a new technology, it has quickly become popular. Recent research shows that 32% of developers used this technology to create applications in 2022.
Cross-platform mobile frameworks used by global developers in 2022
The purpose of this software framework is to provide a way for developers to build mobile applications without having to write separate code for each platform while also leveraging its native capabilities and performance. It is based on React—a JavaScript library for building user interfaces.
The software framework uses the same declarative and component-based approach as React. However, instead of rendering web components, it renders native ones compatible with Android, iOS, and other platforms. As a result, you can create native-like user interfaces using familiar web technologies, including components, props, states, and hooks. Despite this, you can still make high-performance mobile applications. React Native does work on the web, too.
Additionally, it supports hot reloading and fast refresh, which enable you to see the changes in your code without rebuilding the app.
Some of the popular apps that use this software framework are:
Facebook
Instagram
Skype
Airbnb
Uber
Walmart
Discord
Pinterest
Tesla
Bloomberg
What You Need to Know Before Working with React Native
How does React Native work? Before answering this question, you must have some knowledge of React and JavaScript fundamentals. You will also need to install some tools and dependencies on your machine, like:
Node.js, npm, or yarn
Expo CLI or React Native CLI
Android Studio or Xcode
You can follow the official documentation to set up your environment and create your first project using this software framework. Finally, it is essential to have a basic knowledge of mobile app development and the various platforms that it supports.
How Does React Native Work?
React Fundamentals
Before delving into how React Native does work, it is highly recommended to have a comprehensive understanding of the fundamental principles of React. This declarative JavaScript library lets developers create user interfaces (UIs) by breaking them down into reusable pieces called components. These can then be composed together to create intricate UI designs while simultaneously controlling their state and data. Lastly, React uses a virtual DOM to efficiently render and update the UI.
The core concepts of React are:
Components
React applications are constructed using reusable code called components, which can be combined to generate intricate user interfaces. These components are either functions or classes that receive input, commonly referred to as “props,” and in turn, return output, also known as JSX.
For those who do not know, JSX is a syntax extension that allows developers to write HTML-like code in JavaScript. However, remember that React Native does not use CSS and HTML out of the box. For example, here is a simple component that renders a greeting message:
function Greeting(props) { return Hello, {props.name}!; }
It is possible to create a tree structure by nesting components. For example, here is a component that renders a list of greetings:
function GreetingList(props) { return (
{props. names.map((name) => (
))}
); }
Props
Properties—commonly referred to as "props"—are essential inputs that components receive from their parents in React. These props configure the component and provide the necessary data to render its output accurately. In a sense, props are similar to function parameters or attributes in HTML tags, as they serve as a way to pass data between different components in a React-based application.
One crucial factor to note about props is that they are read-only, meaning that components cannot modify them once passed down from their parents. Instead, they can use the data provided by the props to render different outputs or pass them down to their child components, creating a hierarchical structure of interconnected components. For example, here is a component that renders an image with a given source and style:
function Image(props) { return ; }
State
The concept of "state" refers to the internal data managed by components. As a result, the component can keep track of its current state and update its output accordingly. Unlike "props" (passed down from a parent component and cannot be changed by the child component), "state" is mutable. In other words, components can modify their state using a special function called "setState."
The component and its children are re-rendered whenever the state changes to reflect the updated data. For example, here is a component that renders a counter with a button to increment it:
class Counter extends React. Component { constructor(props) { super(props); // Initialize state with a count property this.state = { count: 0 }; } // Define a method to increment the count increment = () => { // Use setState to update the state this.setState((prevState) => { // Return a new state object with the updated count return { count: prevState.count + 1 }; }); }; render() { // Use state to render the output return (
The count is {this.state.count}
); } }
How React Native Uses Native Components as Building Blocks
One of the key features that sets this software framework apart is its use of native components as the building blocks for the user interface. What this means is that, unlike web components, which are designed to be platform-agnostic, this technology employs the same UI elements as native iOS and Android apps. This allows your app to look and feel truly native on both platforms, regardless of the fact that it is written in JavaScript.
To give you an idea of what we mean by "native components," let's take a look at some examples. On Android, a native component could be something as simple as a TextView or a Button. On iOS, it might be a UILabel or a UIButton. These are the building blocks that the software framework uses to construct your app's interface.
But what makes this software framework truly powerful is its ability to map these native components directly to its own set of core components. This means that you can use its own APIs to create your app's UI, without having to worry about the underlying native code. Some core components that map directly to the native platform UI elements are:
View: A generic container that supports layout and styling.
Text: A component for displaying text.
Image: A component for displaying images.
Button: A basic button that handles user interactions.
ScrollView: A container that allows scrolling of its content.
FlatList: A performant component for rendering lists of data.
The components are built using a combination of JavaScript and native code. Thus, they can access the underlying hardware and software of iOS and Android devices, giving them a performance advantage over web components.
It is helpful to be familiar with the core components available to you. These can be utilized independently or with third-party libraries offering even more options.
One such popular library is React Native Elements, which provides a comprehensive collection of user interface components specifically designed for use with this software framework. You can easily create a dynamic and engaging app that meets your needs and requirements by leveraging these resources and knowing how React Native does work.
What is React Native Used For?
This software framework is used for developing mobile applications that can run on multiple platforms using a single codebase. In other words, you can write one app using JavaScript and React and deploy it to Android and iOS devices without writing separate native code for each. Thus, you will save time, money, and resources and ensure consistency and quality across your app.
It is also used for creating interactive and engaging user interfaces that leverage the native capabilities and performance of each platform. It allows you to access native APIs and modules, such as cameras, location, and sensors using JavaScript. You can also use native code to optimize some aspects of your app or implement custom functionality that this software framework does not support.
Conclusion
In this article, we have learned how React Native does work. This robust cross-platform mobile development framework allows you to build high-performance mobile apps using JavaScript. With its ability to develop applications for multiple platforms using a single codebase, it is no wonder that this software framework has become such a popular choice for mobile app development.
