beginners-eslint

eslintrc.js

{
  "env": {
    "browser": true,
    "es2021": true
  },
  "parserOptions": {
    "ecmaVersion": 2021,
    "sourceType": "module"
  },
  "plugins": ["import"],
  "extends": ["eslint:recommended", "plugin:react/recommended"],
  "rules": {
    // Stylistic rules
    "indent": ["warn", 2, { "SwitchCase": 1 }],

    // Enforces consistent linebreak style (unix)
    "linebreak-style": ["warn", "unix"],

    // Enforces the use of single quotes for strings
    "quotes": ["warn", "single"],

    // Enforces semicolons at the end of statements
    "semi": ["warn", "always"],

    // Limits lines of code and comments to 60 characters per line
    "max-len": ["warn", { "code": 60, "comments": 60 }],

    // Best practices
    // Warns against the use of console statements
    "no-console": "warn",

    // Import rules
    // Warns when file extensions are required in import statements
    "import/extensions": ["warn", "never"],

    // JavaScript language features

    // Warns about unreachable code
    "no-unreachable": "warn",

    // Warns about unused expressions
    "no-unused-expressions": "warn",

    // Warns about unused labels
    "no-unused-labels": "warn",

    // Warns about unused variables
    "no-unused-vars": "warn",

    // Warns about empty blocks/statements
    "no-empty": "warn",

    // Warns about empty character classes in regular expressions
    "no-empty-character-class": "warn",

    // Warns about empty function declarations
    "no-empty-function": "warn",

    // Warns about empty object patterns
    "no-empty-pattern": "warn",

    // Warns about unnecessary boolean casts
    "no-extra-boolean-cast": "warn",

    // Warns about unnecessary semicolons
    "no-extra-semi": "warn",

    // Warns about unnecessary lone blocks
    "no-lone-blocks": "warn",

    // Warns about unnecessary function callings
    "no-useless-call": "warn",

    // Warns about unnecessary try/catch blocks
    "no-useless-catch": "warn",

    // Warns about unnecessary string concatenation
    "no-useless-concat": "warn",

    // Warns about unnecessary constructor declarations
    "no-useless-constructor": "warn",

    // Warns about unnecessary escape characters
    "no-useless-escape": "warn",

    // Warns about unnecessary return statements
    "no-useless-return": "warn",

    // Warns about code complexity exceeding a maximum threshold
    "complexity": ["warn", { "max": 15 }],

    // Warns about excessive nested code blocks
    "max-depth": "warn",

    // Warns about files exceeding a maximum number of lines (excluding blank lines and comments)
    "max-lines": [
      "warn",
      { "max": 50, "skipBlankLines": true, "skipComments": true }
    ],

    // Warns about functions exceeding a maximum number of lines (excluding blank lines and comments)
    "max-lines-per-function": [
      "warn",
      { "max": 30, "skipBlankLines": true, "skipComments": true }
    ],

    // Warns about excessive nested callbacks
    "max-nested-callbacks": "warn",

    // Warns about functions exceeding a maximum number of statements
    "max-statements": "warn"
  }
}