.eslintrc.json

{
  "extends": ["eslint:recommended", "plugin:prettier/recommended"],
  "plugins": ["prettier"],
  "rules": {
    "prettier/prettier": "error",
    "no-use-before-define": "off"
  },
  "env": { "es2017": true },
  "parserOptions": { "sourceType": "module", "ecmaVersion": 2018 },
  "overrides": [
    {
      "files": ["*.ts"],
      "parser": "@typescript-eslint/parser",
      "parserOptions": { "project": "./tsconfig.json" },
      "plugins": ["@typescript-eslint"],
      "extends": [
        "eslint:recommended",
        "plugin:@typescript-eslint/eslint-recommended",
        "plugin:@typescript-eslint/recommended",
        "prettier/@typescript-eslint"
      ],
      "rules": {
        "no-use-before-define": "off",
        "@typescript-eslint/no-use-before-define": "off",
        "no-unused-vars": "off",
        "@typescript-eslint/no-unused-vars": ["error", { "argsIgnorePattern": "^_" }]
      }
    },
    {
      "files": ["test/**/*.ts"],
      "env": {
        "jest": true
      }
    }
  ]
}