.eslintrc.js

module.exports = {
  root: true,
  parser: "@typescript-eslint/parser",
  plugins: ["@typescript-eslint", "prettier", "jest"],
  env: {
    node: true,
  },
  extends: ["eslint:recommended", "prettier"],
  rules: {
    "no-var": "error",
    semi: "error",
    "no-multi-spaces": "error",
    "space-in-parens": "error",
    "no-multiple-empty-lines": "error",
    "prefer-const": "error",
    "no-use-before-define": "error",
    "no-undef": "warn",
    "no-param-reassign": "error",
    "no-console": "error",
    "prettier/prettier": [
      "error",
      {
        parser: "typescript",
      },
    ],
  },
  overrides: [
    {
      files: ["**/*.ts"],
      extends: [
        "eslint:recommended",
        "prettier",
        "plugin:@typescript-eslint/recommended",
      ],
    },
    {
      files: ["**/*.js"],
      parser: "espree",
      parserOptions: { ecmaVersion: 2020, sourceType: "module" },
      rules: {},
    },
    {
      files: ["**/*.js"],
      rules: {
        "no-console": "off",
      },
      env: {
        browser: true,
        node: true,
        es6: true,
      },
    },
  ],
};