Setup React App with TypeScript, ESLint and Prettier

08 February 2021

#react #typescript #eslint #prettier #husky #git hooks

Let's create development configuration for a React application with TypeScript, ESLint and Prettier.

Create React App

Let's create a new project with create-react-app tool.

npx create-react-app my-app --template typescript

Then we can run:

npm run eject

It means that all of the configuration will be exposed to you (full project control).

ESLint

ESLint will statically analyze our code to quickly find problems.

npm i --save-dev typescript @typescript-eslint/parser @typescript-eslint/eslint-plugin eslint-config-airbnb-typescript eslint-plugin-react-hooks eslint-plugin-jest eslint-plugin-import

Then we can install the packages for Airbnb config:

npx install-peerdeps --dev eslint-config-airbnb

Prettier

Prettier is an opinionated code formatter. It enforces a consistent style by parsing your code and re-printing it with its own rules that take the maximum line length into account, wrapping code when necessary.

npm i --save-dev prettier eslint-config-prettier eslint-plugin-prettier

ESLint config

Let's create .eslintrc file in the root of the project and paste next code:

// .eslintrc
{
  "parser": "@typescript-eslint/parser",
  "parserOptions": {
    "ecmaFeatures": {
      "jsx": true,
      "useJSXTextNode": true
    },
    "ecmaVersion": 2018,
    "sourceType": "module",
    "project": "./tsconfig.json"
  },
  "extends": [
    "airbnb-typescript",
    "airbnb/hooks",
    "plugin:@typescript-eslint/recommended",
    "plugin:jest/recommended",
    "prettier",
    "prettier/react",
    "prettier/@typescript-eslint",
    "plugin:prettier/recommended"
  ],
  "plugins": ["react", "react-hooks", "@typescript-eslint", "jest"],
  "env": {
    "browser": true,
    "es6": true,
    "jest": true
  },
  "globals": {
    "Atomics": "readonly",
    "SharedArrayBuffer": "readonly"
  },
  "rules": {
    "linebreak-style": "off",
    "react-hooks/rules-of-hooks": "error",
    "react-hooks/exhaustive-deps": "warn",
    "prettier/prettier": [
      "error",
      {
        "endOfLine": "auto"
      }
    ],
    "import/extensions": [
      "error",
      "ignorePackages",
      {
        "js": "never",
        "jsx": "never",
        "ts": "never",
        "tsx": "never"
      }
    ]
  }
}

and add .eslintignore file for prevent lint checking for specific files:

// .eslintignore
.idea
.storybook
.config
node_modules/*
config/*
public/*
scripts/*
src/react-app-env.d.ts
src/reportWebVitals.ts

Prettier config

Let's create .prettierrc file in the root of the project and paste next code:

// .prettierrc
{
  "arrowParens": "always",
  "singleQuote": true,
  "printWidth": 100,
  "jsxBracketSameLine": false,
  "trailingComma": "none"
}

Scripts

In package.json you can add next scripts:

// package.json
"scripts": {
  "start": "node scripts/start.js",
  "build": "node scripts/build.js",
  "test": "node scripts/test.js",
  "lint": "eslint src", // just check errors
  "lint-fix": "eslint src --quiet --fix" // fix lint errors
}

Git hooks

These make sure all our commits are formatted, without having to wait for your CI build to finish.

Install husky:

npm install husky --save-dev

We can add the following to our package.json to have ESLint run before each commit, via husky:

"husky": {
  "hooks": {
    "pre-commit": "npm run lint && npm run test"
  }
}