.eslintrc.json

{
  "parser": "@typescript-eslint/parser",
  "plugins": ["@typescript-eslint", "prettier"],
  "env": {
    "es6": true,
    "node": true,
    "browser": true
  },
  "root": true,
  "extends": [
    "airbnb-base",
    "plugin:@typescript-eslint/recommended",
    "prettier"
  ],
  "rules": {
    "linebreak-style": ["error", "unix"],
    "arrow-parens": ["error", "as-needed"],
    "no-param-reassign": [
      "error",
      {
        "props": false
      }
    ],
    "func-style": [
      "error",
      "declaration",
      {
        "allowArrowFunctions": true
      }
    ],
    "no-use-before-define": [
      "error",
      {
        "functions": false
      }
    ],
    "@typescript-eslint/no-use-before-define": [
      "error",
      {
        "functions": false
      }
    ],
    "import/prefer-default-export": "off",
    "lines-between-class-members": [
      "error",
      "always",
      {
        "exceptAfterSingleLine": true
      }
    ],
    "import/extensions": [
      "error",
      "always",
      {
        "js": "ignorePackages",
        "ts": "never"
      }
    ]
  },
  "settings": {
    "import/resolver": {
      "typescript": {
        "project": ["./tsconfig.browser.json", "./tsconfig.node.json"]
      },
      "node": {
        "extensions": [".ts", ".js"]
      }
    }
  },
  "overrides": [
    {
      "files": ["*.spec.ts"],
      "extends": ["plugin:mocha/recommended"],
      "plugins": ["mocha"],
      "rules": {
        "import/no-extraneous-dependencies": ["off"],
        "mocha/no-mocha-arrows": ["off"],
        "no-unused-expressions": ["off"]
      }
    }
  ]
}