Add document on how to setup ESLint for React app (#1)

README.md

@@ -1,2 +1,18 @@
-# eslint
-Different technologies specific linting rules for ESLint
+# Introduction
+ESLint is a tool to identify and report on patterns found in ECMAScript/JavaScript code, with the goal to make code more consistent and avoid bugs.
+
+This repository will document different technology specific linting rules for ESLint.
+
+At [Osmosys Software Solutions Pvt Ltd](https://osmosys.co/) we standardize the ESLint configuration, which will be used across multiple projects.
+
+# Technologies
+
+- [React with TypeScript](react-typescript-eslint.md)
+
+# TODO
+- Node.js ([Nest.js](https://github.com/nestjs/nest))
+- Vue.js
+- Angular
+
+
+

react-typescript-eslint.md

@@ -0,0 +1,100 @@
+# Introduction
+
+ESLint is a tool to identify and report on patterns found in ECMAScript/JavaScript code, with the goal to make code more consistent and avoid bugs.
+
+This repository will document different technology specific linting rules for ESLint.
+
+At [Osmosys Software Solutions Pvt Ltd](https://osmosys.co/) we standardize the ESLint configuration, which will be used across multiple projects.
+
+# Prerequisite
+
+- React app with TypeScript
+
+Any existing React app with TypeScript. If you don't have one then you can create a basic React app using the following command.
+
+```sh
+npx create-react-app my-app --template typescript
+```
+
+- Node.js
+
+[Node.js](https://nodejs.org/en/) (`^12.22.0`, `^14.17.0`, or `>=16.0.0`) built with SSL support. (If you are using an official Node.js distribution, SSL is always built in.)
+
+# Installation
+
+Install the following packages:
+
+- [eslint@7.32.0](https://github.com/eslint/eslint)
+- [@typescript-eslint/eslint-plugin@4.33.0](https://github.com/typescript-eslint/typescript-eslint/tree/main/packages/eslint-plugin)
+- [eslint-config-standard-with-typescript@21.0.1](https://github.com/standard/eslint-config-standard-with-typescript)
+- [eslint-plugin-import@2.25.3](https://github.com/import-js/eslint-plugin-import)
+- [eslint-plugin-promise@5.1.1](https://github.com/xjamundx/eslint-plugin-promise)
+- [eslint-plugin-react@7.27.0](https://github.com/jsx-eslint/eslint-plugin-react)
+
+
+```sh
+npm i -D eslint@7.32.0 @typescript-eslint/eslint-plugin@4.33.0 eslint-config-standard-with-typescript@21.0.1 eslint-plugin-import@2.25.3 eslint-plugin-promise@5.1.1 eslint-plugin-react@7.27.0
+```
+
+> **Note**: for now assuming we will use `npm` over `yarn`
+
+# Configuration
+
+Create `.eslintrc.js` file in the root directory of your project.
+
+Then add the below configuration in this file.
+
+```js
+module.exports = {
+  root: true,
+  parser: '@typescript-eslint/parser',
+  plugins: [
+    '@typescript-eslint',
+    'react'
+  ],
+  parserOptions: {
+    project: './tsconfig.json',
+    ecmaFeatures: {
+      jsx: true
+    }
+  },
+  extends: [
+    'eslint:recommended',
+    'plugin:@typescript-eslint/recommended',
+    'standard-with-typescript',
+    'plugin:react/recommended'
+  ],
+  settings: {
+    // https://github.com/yannickcr/eslint-plugin-react#configuration
+    react: {
+      'version': 'detect'
+    }
+  },
+  rules: {
+    "@typescript-eslint/semi": ["error", "always"]
+  }
+};
+```
+
+# Usage
+
+Add couple of script commands to run ESLint.
+
+```
+"scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test",
+    "eject": "react-scripts eject",
+    "lint": "eslint src --ext .js,.jsx,.ts,.tsx --max-warnings=0",
+    "lint-fix": "eslint src --ext .js,.jsx,.ts,.tsx --fix"
+  },
+```
+
+**`npm run lint`**
+
+This command will run ESLint and display all the warnings and errors in your code.
+
+**`npm run lint-fix`**
+
+This command will run ESLint, display all the warnings and errors and it will even fix the issues if they are fixable by ESLint.