Understand React Native and Its Usage Process for Android and iOS App Development


React Native has been adding new features and functionality with the motive of helping developers write better code. As the development community gears up for a better ecosystem, additions like React Native Codegen are making building efficient solutions easier and more streamlined.

The launch of Codegen is in line with making React Native development faster by automating repetitive tasks and helping developers extract code scripts.

According to the official release by React Native, Codegen does not qualify as a pillar for development; at best, it’s a tool to make a developer’s work easier.

Care to know more? Read on ahead to find detailed information about Codegen and how a React native app development company can use it.

What is React Native and Codegen Component?

React Native is a mobile application development framework. Using react native, a mobile app development company can build cross-platform applications. They build these applications with JavaScript, which is the base programming language of React and React Native.

Cross-platform applications are easier and cost-efficient to build than native applications. Imagine working only one time to build an application that runs on Android, iOS, and Windows rather than writing the code for each platform separately.

Developers can reuse the same codebase and modify it according to the platform. As a result, the applications are built with speed and at relatively less costs.

While cross-platform compatibility is a primary aspect of React Native, the Codegen component is another useful addition.

Codegen helps generate type-safe components and hooks for the application. What it does is generates scaffolding code, which forms the basic structure on which you can build your application.

You can choose to write all the scaffolding code manually, but with Codegen at your perusal, things can be completed faster.

In React Native, Codegen is automatically invoked when you build an iOS or Android application. Codegen uses TypeScript programming language to write the code for the application components. For coding, Codegen takes reference from the TypeScript definition stored in the files.

In addition to this, Codegen is a command-line tool that analyzes the code and generates type-safe component code. You will get the components and hooks for the codebase automatically when using Codegen.

So, in essence, Codegen eases a developer’s work to a great extent. It reduces development time and effort and automates repetitive tasks. The developers can use the extra time to improve their work further and innovate.

To bring you up to date on the Codegen updates, with React Native 0.70 release, the team brought a unified method to define the Codegen specifications.

The new method works similarly for iOS and Android applications. In the previous versions, the developers had to create a separate file for Android configuration, as build. grade.

Now developers can define the configurations directly into the package.json; 


Following this system, the personnel responsible for library maintenance can get a more consistent experience, especially when they are migrating the codebase to the new architecture.

Before we move on to know how to use Codegen, remember that it’s linked with the build of the application. The scripts developers require for invoking Codegen are available in the react-native NPM repository.

The Process to Use Codegen Component in React Native

To use Codegen, the developers must have an understanding of JSON, as the developers are supposed to supply the required information in the JSON file. The Codegen component generates the required JavaScript code according to the specifications shared with the file.

Here are the basic steps to use Codegen for your development work;

1. Begin by defining the interface of a component in a .d.ts file. Remember to add the prop types and state types of the component you need to auto-generate the code for within the file.

2. Next step is to install the Codegen tool in the form of dev dependency in the project. Use the following command to install React Native Codegen.

npm install -g react-native-codegen 

3. Followed by this, create a .tsx file for the component you wish to generate code for. Next, add the necessary imports for React and components dependencies.

4. Moving forward, you must import the Codegen tool at the top of the .tsx file created initially. Follow the code script to implement step 4; 


5. For the next step, we want the Codegen component to return a JSX element by taking the information for props and ref. For this, use the following code script; 

6. The next step is to use the Codegen tool to generate TypeScript code for the component defined in the file earlier.  

TypeScript code-min

The resultant code can be called MyComponentNative and used the same for other parts of the project. This transforms the component to be used as any other React Native component.

React Native component-min

 This was a basic explanation of how to use the codegen tool. The exact implementation of the same depends on your requirements and project needs.

Given below is an example of how to use Codegen to generate the code for a Button component.

After installation, developers need to create a JSON file for the purpose of defining the components. For your reference, the following codescript represents a JSON file defining a button component; 

JSON file-min

Notice the component Button and its two props defined via JSON file. The component Button’s props are; 

  • Title – which is a type string 
  • onPress – which is a prop function without arguments and return value.

Going ahead, to generate the JavaScript code for the same button component, run the following command; 

react-native-codegen generate MyButton.json MyButton.js  

As a result, the developers can directly access a file named MyButton.js containing type-safe component code.

This summarizes one application of the React Native Codegen component. The same tool can also generate TypeScript interfaces and Flow Types.

Using these two applications, it becomes easier to use type checking and code completion in IDE. Using this function, writing and maintaining code is streamlined.

We Can Also use Codegen with TypeScript; here’s How?

Here too, the developers need to feed a TypeScript with component and hook information. Using this, Codegen can contemplate the contents of the file and generate type-safe code for the component and hook.

To give an example, assuming a TypeScript file, Button.tsx contains the code for a button component. Developers can generate type-safe components with the command;

npx react-native-codegen generate –componentName Button –schema <path/to/Button.tsx> –output <path/to/output/directory>

This command gives instructions to Codegen to generate a type-safe component by the name of Button. Using the TypeScript file path “<path/to/Button.tsx>”, Codegen will save the output directory according to the specifications with the “–output” flag.

Benefits of Codegen for Mobile App Development

When Facebook introduced a new architecture for React Native in 2018, the motivation behind it was fixing some structure and long-standing issues. The purpose is to make it easier to build cross-platform applications. Here are some benefits of the Codegen component in React Native app development.

1. Better Quality of Code:

Using the Codegen component, developers can write error-free code in a fraction of the time as it automates the code generation part.

Moreover, error discovery with Codegen is possible during compile-time as opposed to earlier during runtime. As a result, a mobile app development company ends up saving time and effort that is otherwise spent in debugging.

2. Faster Turnout with Development:

Codegen automates the code generation exercise, at least for repetitive tasks. It auto-generates type-safe components and hooks, allowing the developers to focus on building the core features of the application without stressing too much on the project implementation.

3. Reusable Code:

One of the primary benefits of react native app development is code reusability. Because Codegen is a part of react native, the code this tool generates can be reused.

Moreover, for faster execution, you can also create a separate library of type-safe components and hook codescript generated with Codegen. Using these codescripts will help save a lot of time and effort.

4. Build-Cross Platform Applications:

You can use Codegen to build applications for iOS and Android. Codegen can generate type-safe codescripts for both types of applications exclusive to each of these platforms. As a result, the developers won’t have to write separate code for both iOS and Android.

To Sum it Up

React Native Codegen offers several benefits to the developers of a mobile app development company, helping them create high-quality applications for iOS and Android. Plus, developers will find it easier to build an application when employing Codegen as it helps write high-quality, error-free reusable code.

Using Codegen, you can reduce the work required to write boilerplate code and always have up-to-date and maintainable code. Ultimately, react native’s Codegen is one of the ways to build performance-ready applications.