to consume the types provided by the @types/gtag.js package create a root index.d.ts file then add a triple slash directive at the very top followed with a `declare module` a few lines below:

```ts

/// <reference types="gtag.js" />

declare module 'gtag.js'

```

then you can just call the types from anywhere in your repo without importing anything. I have google.maps called in mine as well

```ts

/// <reference types="google.maps" />

/// <reference types="gtag.js" />

declare module 'google.maps';

declare module 'gtag.js';

```