.eslintrc.json

{
  "overrides": [
    // TypeScript
    {
      "env": {
        "es2021": true,
        "node": true,
        "jest/globals": true
      },
      "files": ["*.tsx", "*.ts"],
      "parser": "@typescript-eslint/parser",
      "plugins": ["jest", "@typescript-eslint"],
      "extends": [
        "eslint:recommended",
        "plugin:@typescript-eslint/recommended",
        "plugin:@typescript-eslint/eslint-recommended"
      ],
      "parserOptions": {
        "ecmaVersion": "latest",
        "sourceType": "module"
      },
      "rules": { "no-fallthrough": 0 }
    },
    // Javascript
    {
      "env": {
        "es2021": true,
        "node": true,
        "jest/globals": true
      },
      "files": ["*.jsx", "*.js"],
      "plugins": ["jest"],
      "extends": ["eslint:recommended"],
      "parserOptions": {
        "ecmaVersion": "latest",
        "sourceType": "module"
      },
      "rules": { "no-extra-semi": 0, "no-fallthrough": 0 }
    }
  ],
  "root": true
}