.eslintrc.json

{
  "root": true,
  "plugins": ["promise", "import", "@typescript-eslint", "prettier"],
  "env": {
    "es6": true,
    "browser": true,
    "node": true
  },
  "parserOptions": {
    "sourceType": "module"
  },
  "extends": ["plugin:import/typescript", "prettier"],
  "rules": {
    "prettier/prettier": "error",
    "camelcase": [
      "error",
      {
        "allow": ["^UNSAFE_"],
        "properties": "always"
      }
    ],
    "one-var": ["error", "never"],
    "prefer-arrow-callback": [
      "error",
      {
        "allowNamedFunctions": true
      }
    ],
    "prefer-spread": "error",
    "prefer-const": [
      "error",
      {
        "destructuring": "all"
      }
    ],
    "no-unused-vars": [
      "error",
      {
        "argsIgnorePattern": "^_"
      }
    ],
    "no-console": ["error", {"allow": ["info", "warn", "error"]}],
    "no-alert": ["error"],
    "no-debugger": ["error"],
    "quotes": [
      "error",
      "single",
      {
        "avoidEscape": true,
        "allowTemplateLiterals": true
      }
    ],
    "jsx-quotes": ["error", "prefer-double"],
    "require-await": "error",
    "import/no-unresolved": [
      "error",
      {
        "commonjs": true,
        "ignore": ["\\.png$", "\\.jpe?g$", "^csstype$"]
      }
    ],
    "no-use-before-define": "warn",
    "import/no-duplicates": 0
  },
  "overrides": [
    {
      "files": ["**/*.{ts,tsx}"],
      "parser": "@typescript-eslint/parser",
      "rules": {
        "@typescript-eslint/adjacent-overload-signatures": "error",
        "@typescript-eslint/ban-types": "error",
        "@typescript-eslint/no-misused-new": "error",
        "@typescript-eslint/consistent-type-definitions": ["error", "interface"],
        "@typescript-eslint/array-type": [
          "error",
          {
            "default": "array-simple"
          }
        ],
        // TS rule overrides
        "camelcase": "off",
        "no-unused-vars": "off",
        "@typescript-eslint/no-unused-vars": [
          "error",
          {
            "argsIgnorePattern": "^_"
          }
        ],
        "no-unused-expressions": "off",
        "@typescript-eslint/no-unused-expressions": [
          "error",
          {
            "allowShortCircuit": true,
            "allowTernary": true,
            "allowTaggedTemplates": true
          }
        ],
        "no-use-before-define": "off",
        "@typescript-eslint/no-use-before-define": "off",
        "no-useless-constructor": "off",
        "@typescript-eslint/no-useless-constructor": "error",
        "@typescript-eslint/prefer-ts-expect-error": "error",
        // TypeScript handles these errors
        "no-dupe-class-members": "off",
        "no-undef": "off",
        "import/default": "off",
        "import/export": "off",
        "import/named": "off"
      }
    },
    {
      "files": "src/**/*.ts",
      "plugins": ["ssr-friendly"],
      "extends": ["plugin:ssr-friendly/recommended"]
    }
  ]
}