.eslintrc.json

{
  "root": true,
  "plugins": ["eslint-plugin-expect-type", "prefer-arrow", "jest"],
  "parserOptions": {
    // Required by eslint-plugin-expect-type.
    //
    // typescript-eslint currently [does not support project
    // references](https://github.com/typescript-eslint/typescript-eslint/issues/2094),
    // so linting requires building first.
    "project": "./tsconfig.base.json"
  },
  "extends": [
    "eslint:recommended",
    "plugin:@typescript-eslint/base",
    "plugin:@typescript-eslint/eslint-recommended",
    "prettier",
    "plugin:eslint-plugin-expect-type/recommended",
    "plugin:eslint-comments/recommended"
  ],
  "rules": {
    // Fix "eslint:recommended".
    "no-ex-assign": "off",
    // Rules that prevent unused code.
    "no-unused-vars": "off",
    "@typescript-eslint/no-unused-vars": [
      "error",
      { "ignoreRestSiblings": true }
    ],
    "eslint-comments/no-unused-disable": "error",
    "no-useless-rename": "error",
    "object-shorthand": "error",
    "no-constant-condition": "off",
    "@typescript-eslint/no-unnecessary-condition": [
      "error",
      { "allowConstantLoopConditions": true }
    ],
    "@typescript-eslint/await-thenable": "error",
    "@typescript-eslint/no-unnecessary-type-assertion": "error",
    "jest/no-disabled-tests": "error",
    "jest/no-focused-tests": "error",
    // Consistency rules.
    "prefer-arrow/prefer-arrow-functions": "error",
    "arrow-body-style": "error",
    "no-restricted-syntax": [
      "error",
      {
        "selector": "ExportDefaultDeclaration",
        "message": "Prefer named exports"
      }
    ],
    "curly": "error",
    "no-use-before-define": "error",
    "@typescript-eslint/no-confusing-void-expression": "error"
  }
}