.eslintrc.json

{
  "root": true,

  "env": {
    "node": true,
    "es6": true,
    "browser": true,
    "jest": true
  },

  "settings": {
    "react": {
      "version": "detect"
    }
  },

  "globals": {
    "Atomics": "readonly",
    "SharedArrayBuffer": "readonly"
  },

  "overrides": [
    {
      "parser": "@typescript-eslint/parser",
      "files": ["**/*.ts?(x)"],
      "parserOptions": {
        "ecmaFeatures": {
          "jsx": true
        },
        "ecmaVersion": 2018,
        "sourceType": "module"
      },
      "extends": [
        "eslint:recommended",
        "plugin:react/recommended",
        "plugin:@typescript-eslint/eslint-recommended",
        "plugin:@typescript-eslint/recommended",
        "prettier",
        "prettier/@typescript-eslint",
        "prettier/babel",
        "prettier/react",
        "plugin:import/errors",
        "plugin:import/warnings",
        "plugin:import/typescript"
      ],

      "plugins": ["@typescript-eslint"],
      "rules": {
        "@typescript-eslint/explicit-function-return-type": [
          "warn",
          {
            "allowExpressions": false,
            "allowTypedFunctionExpressions": true,
            "allowHigherOrderFunctions": true
          }
        ],
        "@typescript-eslint/explicit-member-accessibility": [
          "warn",
          {
            "accessibility": "no-public",
            "overrides": {
              "accessors": "explicit",
              "constructors": "no-public",
              "methods": "explicit",
              "properties": "explicit",
              "parameterProperties": "off"
            }
          }
        ],
        "@typescript-eslint/indent": ["error", 2],
        "@typescript-eslint/no-non-null-assertion": "off",
        "@typescript-eslint/no-parameter-properties": [
          "warn",
          {
            "allows": [
              "private",
              "protected",
              "public",
              "private readonly",
              "protected readonly",
              "public readonly"
            ]
          }
        ],
        "@typescript-eslint/no-unused-vars": "off",
        "@typescript-eslint/no-use-before-define": [
          "error",
          {
            "functions": false,
            "typedefs": false
          }
        ]
      }
    },
    {
      "files": ["**/*.js?(x)"],
      "parser": "babel-eslint",
      "parserOptions": {
        "ecmaVersion": 2018,
        "sourceType": "module",
        "ecmaFeatures": {
          "jsx": true
        }
      },

      "extends": [
        "eslint:recommended",
        "plugin:react/recommended",
        "prettier",
        "prettier/babel",
        "prettier/react",
        "plugin:import/errors",
        "plugin:import/warnings"
      ],

      "plugins": [],

      "rules": {}
    }
  ]
}