ANNOUNCEMENT

DO NOT MODIFY OR CHANGE THE CODE BEFORE CONFIRMED BY DOOBOOLAB. THIS REPOSITORY IS USED IN DOOBOO-CLI.

React Native TS Boilerplate

Specification

• react-native
• react-navigation
• typescript
• localization
• styled-components
• ts-jest
• react-hook
• @testing-library/react-native
• @testing-library/react-hooks
• prettier

Gain points

1. Sample of context-api with `react-hook` (`useContext`).
2. Know how to structure react native app with typescript.
3. Know how to navigate between screens with `react-navigation`.
4. Know how to write test code with `testing-library`.
5. Know how to `lint` your project with `eslint` for both `ts` and maybe some `js`.
6. Know how to localize your project.

INSTALL

npm install && npm start
// or
yarn && yarn start

Structures

app/
├─ .doobooo // necessary if using dooboo-cli
├─ assets
│  └─ icons // app icons
│  └─ images // app images like background images
├─ node_modules/
├─ src/
│  └─ apis
│  └─ components
│     └─ navigations
│     └─ screen
│     └─ shared
│  └─ providers
│  └─ utils
│  └─ App.tsx
├─ test/
├─ .buckconfig
├─ .flowconfig
├─ .gitattributes
├─ .gitignore
├─ .watchmanconfig
├─ app.json
├─ babel.config.js
├─ index.js
├─ jest.config.js
├─ package.json
├─ README.md
├─ STRINGS.js
├─ tsconfig.json
└─ eslint.json

Running the project

Running the project is as simple as running

npm run start

This runs the start script specified in our package.json, and will spawn off a server which reloads the page as we save our files. Typically the server runs at http://localhost:8080, but should be automatically opened for you.

Testing the project

Testing is also just a command away:

npm test

Result

> jest -u

 PASS  src/components/shared/__tests__/Button.test.tsx
 PASS  src/components/screen/__tests__/Intro.test.tsx
 › 2 snapshots written.

Snapshot Summary
 › 2 snapshots written in 1 test suite.

Test Suites: 2 passed, 2 total
Tests:       5 passed, 5 total
Snapshots:   2 added, 4 passed, 6 total
Time:        3.055s, estimated 6s
Ran all test suites

Writing tests with Jest

We've created test examples with jest-ts in src/components/screen/__tests__ and src/components/shared/__tests__. Since react is component oriented, we've designed to focus on writing test in same level of directory with component. You can simply run npm test to test if it succeeds and look more closer opening the source.

Vscode prettier and eslint setup

"eslint.enable": true,
"eslint.validate": [
    "javascript",
    "javascriptreact",
    "typescript",
    "typescriptreact"
],
// prettier extension setting
"editor.formatOnSave": true,
"[javascript]": {
    "editor.defaultFormatter": "esbenp.prettier-vscode"
},
"[javascriptreact]": {
    "editor.defaultFormatter": "esbenp.prettier-vscode"
},
"[typescript]": {
    "editor.defaultFormatter": "esbenp.prettier-vscode"
},
"[typescriptreact]": {
    "editor.defaultFormatter": "esbenp.prettier-vscode"
},
"prettier.singleQuote": true,
"prettier.trailingComma": "all",
"prettier.arrowParens": "always",
"prettier.jsxSingleQuote": true

Using Context Api

Whenever you add your own Context provider you can add it to providers/ and use it inside of providers/index.tsx

• Splitting provider is preferred

// Add providers here
const RootProvider = ({
  initialThemeType,
  children,
}: Props): React.ReactElement => {
  return (
    <AppProvider>
      <ThemeProvider
        initialThemeType={initialThemeType ? ThemeType.LIGHT : ThemeType.DARK}
      >
        {children}
      </ThemeProvider>
    </AppProvider>
  );
};

The RootProvider is being used at App.tsx and test files easily

// App.tsx
function App(): React.ReactElement {
  return (
    <RootProvider>
      <SwitchNavigator />
    </RootProvider>
  );
}

// test files
const component = (props): React.ReactElement => {
  return (
    <RootProvider initialThemeType>
      <Intro {...props} />
    </RootProvider>
  );
};

using consistent theme(ThemeType.LIGHT as default) explicitly is encouraged in testing for avoiding unexpected snapshot test errors

Localization

We've defined Localization strings in STRINGS.js which is in root dir. We used react-native-localize pacakage for this one which use i18n-js together.

• How it is installed

  import * as Localization from 'react-native-localize';
  
  import en from './assets/langs/en.json';
  import i18n from 'i18n-js';
  import ja from './assets/langs/ja.json';
  import ko from './assets/langs/ko.json';
  
  const locales = Localization.getLocales();
  
  if (Array.isArray(locales)) {
    i18n.locale = locales[0].languageTag;
  }
  
  i18n.fallbacks = true;
  i18n.translations = { en, ko, ja };
  
  export const getString = (param: string, mapObj?: object): string => {
    if (mapObj) {
      i18n.t(param, mapObj);
    }
    return i18n.t(param);
  };

• How it is used

  Import locales in assets/langs. Currently, ko.json and en.json is installed. If you want to add more languages you can add it in STRINGS.ts and i18n.translations = { en, ko }; add more languages inside i18n.translations.

  import { getString } from '../../../STRINGS';
  
  getString('LOGIN');

• How it is mocked

  Fixed jest setup by adding following in __mocks__/react-native-localize.ts.

  interface Locale {
    countryCode: string;
    languageTag: string;
    languageCode: string;
    isRTL: boolean;
  }
  const getLocales = (): Locale[] => [
    {
      countryCode: 'US',
      languageTag: 'en-US',
      languageCode: 'en',
      isRTL: false,
    },
    {
      countryCode: 'EC',
      languageTag: 'es-EC',
      languageCode: 'es',
      isRTL: false,
    },
  ];
  
  const findBestAvailableLanguage = (): Partial<Locale> => ({
    languageTag: 'es',
    isRTL: false,
  });
  
  const getNumberFormatSettings = (): object => ({
    decimalSeparator: '.',
    groupingSeparator: ',',
  });
  
  const getCalendar = (): string => 'gregorian'; // or "japanese", "buddhist"
  const getCountry = (): string => 'ES'; // the country code you want
  const getCurrencies = (): [string] => ['USD']; // can be empty array
  const getTemperatureUnit = (): string => 'celsius'; // or "fahrenheit"
  const getTimeZone = (): string => 'Ecuador/Guayaquil'; // the timezone you want
  const uses24HourClock = (): boolean => true;
  const usesMetricSystem = (): boolean => true;
  
  const addEventListener = jest.fn();
  const removeEventListener = jest.fn();
  
  export {
    findBestAvailableLanguage,
    getLocales,
    getNumberFormatSettings,
    getCalendar,
    getCountry,
    getCurrencies,
    getTemperatureUnit,
    getTimeZone,
    uses24HourClock,
    usesMetricSystem,
    addEventListener,
    removeEventListener,
  };

React version

16.9

React Native version

0.61

React navigation

4