Hung Dao

Freelance Fullstack Developer

My React Native Stack After 1 Year

In this post, I'm going to share my React Native project structure, configurations and some tips. It contains most of the things I've learnt after 1 year of development with React Native, from the creation to the distribution.
I created a Github repository called typescript-react-native-starter that I now use for all my projects.
So I hope it's helpful for other developers who are new with React Native. And you are welcome to make PR :D

Features

I started to use Typescript recently after several projects which made me understand the importance of typed variables. It might take some time to learn at first but it's worth it. You might avoid hours maybe days of debugging thanks to Typescript.
Plus it makes your code self-documenting which is crucial for projects with severals developers.

Typescript

Flux State management

Redux: predictable state container
Redux Persist: offline store
Redux Saga: side effect model for Redux
typesafe-actions: create typesafe actions easily
      import { action } from 'typesafe-actions';
      import * as types from './actionTypes';

      export const myAction = payload => action(types.MY_ACTION_TYPE, payload);

Navigation

React Navigation: easy-to-use navigation solution based on Javascript

Unit testing

Unit tests with JestEnzyme and react-native-testing-library
Codecov: coverage report

CI/CD

Run linting pre-commit and unit testing pre-push with husky's hooks
Placeholder App Icon: useful for uploading your app to beta quickly with Fastlane
App Icon generator: generate all required sizes, label and annotate icon.Placeholder feature graphic and screenshot to upload beta android app quickly

Linting

Tslint configured with Airbnb styles
Vscode Prettier compatible

Internationalization and localization

react-native-localization: easy to use package for i18n

Others

Cocoapods: iOS dependencies manager
autobind-decorator: bind your component's functions easily with a decorator
// Before
handleClick()  {...}

<button onClick={ this.handleClick.bind(this) }></button>

// After
@boundMethod
handleClick() {...}

<button onClick={ this.handleClick }></button>

Project Structure

The structure I used is inspired from many sources so you might find this familiar. I like to seperate my files by category except for some special ones like App.tsx, store.ts,...
The publishing folder also contains some useful placeholder images to deploy your app.
For example, in order to deploy your app on Google Play, even for Internal Testing, you would have to add screenshots, feature graphics,... It was ok at first but after several projects, it's kinda annoying so I decided to create some placeholder images for that.
├── __tests__                            // Unit tests
│   ├── App.test.tsx                     // App component's tests
│   ├── components
│   │   └── MyComponent.test.txs
│   └── ...
├── android
├── app.json
├── assets                               // All assets: images, videos, ...
├── index.js
├── ios
├── publishing                           // Icon, screenshots, preview,... for App Store & Play Store
└── src
    ├── App.tsx
    ├── actions                          // Actions
    │   ├── actionTypes.ts               // Action types
    │   └── app.ts                       // appReducer's actions
    ├── components                       // Components
    │   └── MyComponent.tsx
    ├── constants                        // Colors, sizes, routes,...
    │   └── strings.ts                   // i18n
    ├── containers                       // Screens, pages,...
    ├── lib                              // Libraries, services,...
    ├── index.tsx                        // Root component
    ├── reducers                         // Reducers
    │   └── app.ts                       // appReducer
    ├── sagas                            // Redux sagas
    ├── store.ts
    ├── types                            // Type declarations
    │   └── index.d.ts
    └── utils                            // Utilities

Useful tips

This section is for completely random but useful tips, feel free to share yours in the comment or make a PR

NavigationService

You can navigate without navigation prop by using NavigationService from src/lib/NavigationService.ts
import NavigationService from '../lib/NavigationService';

//...

NavigationService.navigate('ChatScreen', { userName: 'Lucy' });

Cocoapod

When you run react-native link and the linked library has podspec file, then the linking will use Podfile. To disable this feature, remove
# Add new pods below this line
from line 24 in ios/Podfile

Static bundle

The static bundle is built every time you target a physical device, even in Debug. To save time, the bundle generation is disabled in Debug

react-native-screens

You can use react-native-screens with react-navigation in order to improve memory consumption
Install and follow steps in Usage with react-navigation (without Expo) from react-native-screens
Open ./src/index.tsx and uncomment
// import { useScreens } from 'react-native-screens';
// useScreens();

Responsiveness

Avoid as much as you can "absolute" position and hard values (100, 300, 1680,...) especially for big ones.Use flex box and % values insteadIf you have to use hard values, I have this normalize function for adapting hard values accordingly to the screen's width or height. I might upload it on the repository later:
import { Dimensions, Platform, PixelRatio } from 'react-native';

export const { width: SCREEN_WIDTH, height: SCREEN_HEIGHT } = Dimensions.get(
  'window',
);

// based on iphone X's scale
const wscale = SCREEN_WIDTH / 375;
const hscale = SCREEN_HEIGHT / 812;

export function normalize(size, based = 'width') {
  const newSize = based === 'height' ? size * hscale : size * wscale;
  if (Platform.OS === 'ios') {
    return Math.round(PixelRatio.roundToNearestPixel(newSize));
  } else {
    return Math.round(PixelRatio.roundToNearestPixel(newSize)) - 2;
  }
}
So now I can use:
// iphone X
normalize(100) // = 100

// iphone 5s
normalize(100) // = maybe 80

// You can choose either "width" (default) or "height" depend on cases:
container = {
  width: normalize(100, "width"), // "width" is optional, it's default
  height: normalize(100, "height")
}
Before pushing, test your app on 3 differents emulators: iphone5s (small), iphone 8 (medium) and iphone Xs Max (big)

Beta distribution with Fastlane

- Install fastlane
  # Using RubyGems
  sudo gem install fastlane -NV

  # Alternatively using Homebrew
  brew cask install fastlane

iOS

- Open your project Xcode workspace and update your app's Bundle Identifier and Team
- Initialize fastlane
  cd <PROJECT_NAME>/ios
  fastlane init
- Distribute your app
fastlane beta

Android

- Open your project with Android Studio and update your app's applicationId in build.gradle (Module: app) file
- Select Generated Signed Bundle / APK... from the Build menu
- Next then Create new... under Key store path then Next and Finish
- The first time you deploy your application, you MUST upload it into Google Play Console manually. Google don't allow to use theirs APIs for the first upload.Create your application in the Google Play Console (unlike for iOS Fastlane cannot do that for you)
- Make sure that these 4 checkmark icons are green
Recommended order: Pricing & distribution, Content rating, Store listing and App releases
You can find the required assets for Store listing in the publishing/android folder
- Initialize fastlane
  cd <PROJECT_NAME>/android
  fastlane init
- Use the Fastfile from publishing
cp publishing/android/fastlane/Fastfile android/fastlane
- Distribute your app
There is no official plugin to automatically upgrade android version code (unlike the iOS lane).
Before each deployment, be sure to manually upgrade the versionCodevalue inside android/app/build.gradle.

More

- Checkout the Fastlane's beta distribution guide for more details
- Fastlane's documentation for React Native

Apple Store Connect's missing compliance

If you dont' use Fastlane and you don't want to Provide Export Compliance Information at every push , then add this to your Info.plist
Note that you might have to set that to <true/> if your app uses encryption

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