.eslintrc.json

{
  "root": true,
  "extends": [
    "eslint:recommended",
    "plugin:prettier/recommended",
    "plugin:@typescript-eslint/eslint-recommended",
    "plugin:@typescript-eslint/recommended"
  ],
  "ignorePatterns": "lib/**/*",
  "env": {
    "node": true,
    "mocha": true,
    "es6": true
  },
  "parserOptions": {
    "ecmaVersion": 2019
  },
  "plugins": [
    "@typescript-eslint",
    "prettier"
  ],
  "rules": {
    "no-restricted-properties": [
      "error",
      {
        "object": "describe",
        "property": "only"
      },
      {
        "object": "it",
        "property": "only"
      },
      {
        "object": "context",
        "property": "only"
      }
    ],
    "prettier/prettier": "error",
    "no-console": "error",
    "valid-typeof": "error",
    "eqeqeq": [
      "error",
      "always",
      {
        "null": "ignore"
      }
    ],
    "strict": [
      "error",
      "global"
    ],
    "no-restricted-syntax": [
      "error",
      {
        "selector": "TSEnumDeclaration",
        "message": "Do not declare enums"
      },
      {
        "selector": "BinaryExpression[operator=/[=!]==/] Identifier[name='undefined']",
        "message": "Do not strictly check undefined"
      },
      {
        "selector": "BinaryExpression[operator=/[=!]==/] Literal[raw='null']",
        "message": "Do not strictly check null"
      },
      {
        "selector": "BinaryExpression[operator=/[=!]==?/] Literal[value='undefined']",
        "message": "Do not strictly check typeof undefined (NOTE: currently this rule only detects the usage of 'undefined' string literal so this could be a misfire)"
      }
    ],
    "@typescript-eslint/no-require-imports": "off"
  },
  "overrides": [
    {
      "files": [
        "test/**/*ts"
      ],
      "rules": {
        // chat `expect(..)` style chaining is considered
        // an unused expression
        "@typescript-eslint/no-unused-expressions": "off"
      }
    }
  ]
}