Example Project Setup with NextJs, Typescript, Eslint, Jest and Emotion.

Dependency Versions

• NextJs v10.0.5
• react v17.0.1
• Typescript v4.1.3
• @emotion/react v11.1.4

Usage of this example setup

0. setup node env

   nvm use || npm install
1. remove unwanted files in public/, src/
2. add .env and other .env files
3. preview dev progress on http://localhost:3000/

   npm run dev
4. read Setup for notes

Setup

0. install nvm in the os

1. nvm install node
   git init
2. add .gitignore

3. node -v > .nvmrc

4. npm init -y

NextJs

1. npm i -S next react react-dom
2. add a script to your package.json like this:

   {
     "scripts": {
       "dev": "next dev",
       "build": "next build",
       "start": "next start"
     }
   }

Typescript

1. npm i -D typescript @types/react @types/node
2. create tsconfig.json

   {
     "compilerOptions": {
       "target": "esnext",
       "lib": ["dom", "dom.iterable", "esnext"],
       "allowJs": true,
       "allowSyntheticDefaultImports": true,
       "alwaysStrict": true,
       "skipLibCheck": true,
       "strict": false,
       "forceConsistentCasingInFileNames": true,
       "noEmit": true,
       "noFallthroughCasesInSwitch": true,
       "noUnusedLocals": true,
       "noUnusedParameters": true,
       "esModuleInterop": true,
       "module": "esnext",
       "moduleResolution": "node",
       "resolveJsonModule": true,
       "isolatedModules": true,
       "jsx": "preserve",
       "baseUrl": "./src"
     },
     "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx"],
     "exclude": ["node_modules", "next.config.js"]
   }

Create Pages

1. create src/pages folder (or pages)
2. create pages.tsx under src/pages/ (i.e. src/pages/index.tsx for / route)

Eslint and Prettier

1. npm i -D eslint @typescript-eslint/parser @typescript-eslint/eslint-plugin eslint-plugin-react eslint-import-resolver-typescript
   npm i -D eslint-config-airbnb eslint-plugin-jsx-a11y eslint-plugin-import eslint-plugin-react-hooks
   npm i -D prettier eslint-config-prettier eslint-plugin-prettier
2. create .eslintrc.js

   module.exports = {
     env: {
       browser: true,
       node: true,
       es2020: true,
       jest: true,
     },
     parser: '@typescript-eslint/parser', // Specifies the ESLint parser
     parserOptions: {
       ecmaVersion: 2020,
       sourceType: 'module',
       ecmaFeatures: {
         jsx: true,
       },
     },
     plugins: ['@typescript-eslint', 'react', 'react-hooks', 'prettier'],
     extends: [
       'airbnb',
       'plugin:@typescript-eslint/recommended',
       'plugin:react/recommended',
       'plugin:import/errors',
       'plugin:import/warnings',
       'plugin:import/typescript',
       'prettier',
       'prettier/@typescript-eslint',
       'prettier/react',
       'plugin:prettier/recommended', // Enables eslint-plugin-prettier and displays prettier errors as ESLint errors. Make sure this is always the last configuration in the extends array.
     ],
     rules: {
       '@typescript-eslint/no-unused-vars': [
         'error',
         {
           vars: 'all',
           args: 'after-used',
           ignoreRestSiblings: false,
         },
       ],
       '@typescript-eslint/no-explicit-any': 0,
       '@typescript-eslint/explicit-function-return-type': 0,
       '@typescript-eslint/no-namespace': 0,
       '@typescript-eslint/explicit-module-boundary-types': 0,
       'import/extensions': [
         1,
         { extensions: ['.js', '.jsx', '.ts', '.tsx'] },
       ],
       'import/no-extraneous-dependencies': [
         'error',
         {
           devDependencies: true,
         },
       ],
       'react/jsx-filename-extension': [
         1,
         { extensions: ['.js', '.jsx', '.ts', '.tsx'] },
       ],
       'react/react-in-jsx-scope': 0,
       'react/jsx-first-prop-new-line': 0,
       'react/prop-types': 0,
       'react/jsx-props-no-spreading': [2, { custom: 'ignore' }],
       'jsx-a11y/anchor-is-valid': [
         'error',
         {
           components: ['Link'],
           specialLink: ['hrefLeft', 'hrefRight'],
           aspects: ['invalidHref', 'preferButton'],
         },
       ],
       'prettier/prettier': 2,
       'react-hooks/rules-of-hooks': 2,
       'react-hooks/exhaustive-deps': 2,
       'no-bitwise': 2,
     },
     settings: {
       'import/resolver': {
         node: {
           extensions: ['.js', '.jsx', '.ts', '.tsx'],
         },
         typescript: {},
       },
       react: {
         version: 'detect', // Tells eslint-plugin-react to automatically detect the version of React to use
       },
     },
   };
3. create .prettierrc.js

   module.exports = {
     semi: true,
     trailingComma: 'es5',
     singleQuote: true,
     printWidth: 80,
     tabWidth: 2,
   };

Jest

1. npm i -D jest babel-jest @types/jest @next/env

2. add scripts in package.json

   "scripts": {
     "test": "jest",
     "test:watch": "jest --watch",
     "test:coverage": "jest --coverage"
   },

3. create jest.config.js

   module.exports = {
     moduleFileExtensions: ['ts', 'tsx', 'js'],
     testRegex: '(/__tests__/.*|(\\.|/)(test|spec))\\.(jsx?|js?|tsx?|ts?)$',
     globals: {
       NODE_ENV: 'test',
     },
     snapshotSerializers: ['enzyme-to-json/serializer'],
     transform: {
       '^.+\\.(j|t)sx?$': 'babel-jest',
     },
     coveragePathIgnorePatterns: [
       '/node_modules/',
       'jest.setup.js',
       '<rootDir>/configs/',
       'jest.config.js',
       '.json',
       '.snap',
     ],
     setupFiles: ['<rootDir>/jest/jest.setup.js'],
     coverageReporters: ['json', 'lcov', 'text', 'text-summary'],
     moduleNameMapper: {
       '\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
         '<rootDir>/__mocks__/mocks.js',
       '\\.(css|less|scss)$': '<rootDir>/__mocks__/mocks.js',
     },
     moduleDirectories: ['node_modules', 'src'],
   };

4. create babel.config.js

   module.exports = {
     presets: ['next/babel'],
   };

5. create jest/jest.setup.js

   import { join } from 'path';
   import { loadEnvConfig } from '@next/env';
   
   // to load '.env' files in test
   loadEnvConfig(join(__dirname, '../'));

6. change env in .eslintrc.js

   env: {
     browser: true,
     node: true,
     jest: true
   },

EmotionJs

1. npm i -S @emotion/react
   npm i -D @emotion/babel-plugin @emotion/eslint-plugin @emotion/jest

2. change babel.config.js

   module.exports = {
     presets: [
       [
         'next/babel',
         {
           'preset-react': {
             runtime: 'automatic',
             importSource: '@emotion/react',
           },
         },
       ],
     ],
     plugins: ['@emotion/babel-plugin'],
   };

3. add rules and plugins to .eslintrc.js

   module.exports = {
     // ...
     rules: {
       // ...
       '@emotion/no-vanilla': 'error',
       '@emotion/import-from-emotion': 'error',
       '@emotion/styled-import': 'error',
     },
     // ...
     plugins: [
       '@emotion',
       // ...
     ],
     // ...
   };

4. add jest/jest.setupAfterEnv.js

   import { matchers } from '@emotion/jest';
   
   expect.extend(matchers);

5. add serializers and setup files to jest/jest.config.js

   // ...
   snapshotSerializers: ['@emotion/jest/serializer'],
   // ...
   setupFilesAfterEnv: ['<rootDir>/jest.setupAfterEnv.js'],
   // ...

6. add to tsconfig.json

   {
     "compilerOptions": {
       "jsxImportSource": "@emotion/react"
     }
   }

Deploy to Github Pages

(deploy to /docs intead of using gh-pages branch; replace {folder} with the project name in github repo)

1. add .env.production

   NEXT_PUBLIC_LINK_PREFIX=/{folder}
2. create LINK_PREFIX in next.config.js

   const LINK_PREFIX = process.env.NEXT_PUBLIC_LINK_PREFIX || '';
   module.exports = () => ({
     basePath: LINK_PREFIX,
   });
3. change scripts in package.json

   {
     "scripts": {
       "export": "NODE_ENV=production npm run build && next export -o docs && touch docs/.nojekyll"
     }
   }