tsconfig.json

{
  "include": ["src", "types", "public/postbuild.js"],
  "exclude": ["node_modules"],
  "extends": "@snowpack/app-scripts-react/tsconfig.base.json",
  "compilerOptions": {
    // You can't currently define paths in your 'extends' config,
    // so we have to set 'baseUrl' & 'paths' here.
    // Don't change these unless you know what you're doing.
    // See: https://github.com/microsoft/TypeScript/issues/25430
    "baseUrl": "./",
    /* more strict checking for errors that per-file transpilers like `esbuild` would crash */
    "isolatedModules": true,
    "paths": { "*": ["web_modules/.types/*"] },
    // Feel free to add/edit new config options below:
    // ...
    "target": "ES6",
    "allowJs": true,
    "lib": ["dom", "esnext"],
    "esModuleInterop": true,
    "jsx": "react",
    "types": ["snowpack-env", "jest", "testing-library__jest-dom"]
  }
}