.eslintrc.json

{
  "parser": "@typescript-eslint/parser",
  "parserOptions": {
    "ecmaVersion": 2020,
    "sourceType": "module"
  },
  "plugins": [
    "@typescript-eslint",
    "import"
  ],
  "extends": [
    "eslint:recommended",
    "plugin:@typescript-eslint/recommended"
  ],
  "rules": {
    // Possible Errors
    "no-console": "warn",
    // Warn about console statements
    "no-debugger": "warn",
    // Warn about debugger statements

    // Best Practices
    "curly": "error",
    // Require curly braces for all control statements
    "eqeqeq": [
      "error",
      "always"
    ],
    // Require === and !==
    "no-eval": "error",
    // Disallow eval()

    // Variables
    "no-unused-vars": "off",

    "import/order": [
      "error",
      {
        "groups": [
          "builtin",
          "external",
          "internal",
          "parent",
          "sibling",
          "index",
          "object",
          "type"
        ],
        "alphabetize": { "order": "asc", "caseInsensitive": true }
      }
    ],
    // Disabled as @typescript-eslint/no-unused-vars will handle this
    "@typescript-eslint/no-unused-vars": [
      "warn",
      // Warn about unused variables
      {
        "vars": "all",
        "args": "after-used",
        "ignoreRestSiblings": true
      }
    ],
    // Stylistic Issues
    "semi": [
      "error",
      "always"
    ],
    // Require semicolons
    "quotes": [
      "error",
      "single"
    ],
    // Require single quotes
    "indent": [
      "error",
      2
    ],
    // 2-space indentation

    // TypeScript Specific Rules
    "@typescript-eslint/explicit-function-return-type": "off",
    // Turn off explicit return types for functions
    "@typescript-eslint/no-explicit-any": "warn",
    // Warn about the use of any type
    "@typescript-eslint/no-non-null-assertion": "error",
    // Warn about non-null assertions
    "@typescript-eslint/no-inferrable-types": [
      "warn",
      // Warn about inferrable types
      {
        "ignoreParameters": true
      }
    ],
    // Code Complexity
    "complexity": [
      "warn",
      {
        "max": 10
      }
    ],
    // Warn if function has a complexity over 10
    "max-depth": [
      "warn",
      4
    ],
    // Warn if blocks nested too deeply
    "max-lines": [
      "warn",
      {
        "max": 300,
        "skipComments": true
      }
    ],
    // Warn if a file is longer than 300 lines
    "max-params": [
      "warn",
      5
    ],
    // Warn if function has more than 5 parameters
    "max-statements": [
      "warn",
      10
    ]
    // Warn if function has more than 10 statements
  },
  "overrides": [
    {
      "files": [
        "*.test.ts",
        "*.spec.ts"
      ],
      "env": {
        "jest": true
        // Add Jest global variables for test files
      }
    }
  ]
}