.eslintrc.json

{
  "extends": [
    "airbnb-base"
  ],
  "rules": {
    "func-names": "off",

    "prefer-object-spread": "off",
    "import/prefer-default-export": "off",
    "import/extensions": "off",
    "import/no-unresolved": "off",
    "import/no-extraneous-dependencies": "off",
    "class-methods-use-this": "off",
    "no-await-in-loop": "off",
    "eqeqeq": "off",
    "no-restricted-syntax": "off",
    "max-len": ["error", { "code": 120 }]
  },
  "env": {
    "node": true
  },
  "overrides": [
    {
      "files": [
        "*.{ts,tsx}"
      ],
      "plugins": [
        "@typescript-eslint"
      ],
      "extends": [
        "plugin:@typescript-eslint/recommended-requiring-type-checking",
        "airbnb-typescript/base"
      ],
      "parser": "@typescript-eslint/parser",
      "parserOptions": {
        "project": "./tsconfig.json",
        "ecmaVersion": 2020,
        "tsconfigRootDir": "."
      },
      "rules": {
        "import/prefer-default-export": "off",

        // BEGIN ERRORS
        "@typescript-eslint/no-non-null-assertion": "error",
        "@typescript-eslint/no-require-imports": "error",
        "@typescript-eslint/no-unused-vars": "error",
        "@typescript-eslint/restrict-template-expressions": [
          "error",
          { "allowNumber": true, "allowBoolean": true, "allowNullish": true }
        ],
        "@typescript-eslint/restrict-plus-operands": [
          "error",
          { "skipCompoundAssignments": true }
        ],

        // This prevents declarations like `interface ISomething { ... }`
        "@typescript-eslint/naming-convention": [
          "error",
          {
            "selector": "interface",
            "format": ["PascalCase"],
            "custom": {
              "regex": "^I[A-Z]",
              "match": false
            }
          }
        ],

        // BEGIN DISABLED. Some of these are disabled just to prevent warnings.
        "@typescript-eslint/explicit-member-accessibility": "off",
        "@typescript-eslint/no-unnecessary-type-assertion": "off",
        "@typescript-eslint/explicit-function-return-type": "off",
        "@typescript-eslint/no-explicit-any": "off",
        "@typescript-eslint/no-unsafe-call": "off",
        "@typescript-eslint/no-unsafe-assignment": "off",
        "@typescript-eslint/no-unsafe-member-access": "off",
        "@typescript-eslint/unbound-method": "off",
        "@typescript-eslint/ban-types": "off",
        "@typescript-eslint/explicit-module-boundary-types": "off",
        "@typescript-eslint/no-unsafe-return": "off",
        "@typescript-eslint/no-empty-function": "off",
        "@typescript-eslint/no-redundant-type-constituents": "off"
      }
    },
    {
      "files": [
        "test/**/*.{ts,tsx}",
        "*.test.{ts,tsx}"
      ],
      "plugins": [
        "@typescript-eslint"
      ],
      "rules": {
        // Allow ! in tests.
        "@typescript-eslint/no-non-null-assertion": "off",

        // Allow tests to create odd string templates if they want.
        "@typescript-eslint/restrict-template-expressions": "off",
        "@typescript-eslint/ban-ts-comment": "off"
      }
    }
  ]
}