Type declaration for GM_* APIs in Violentmonkey.
The APIs should be almost the same as those in Tampermonkey, so @types/tampermonkey should also work.
$ npm i @violentmonkey/types
Add @violentmonkey/types to a .d.ts file.
For example, create src/vm.d.ts with the following content:
import '@violentmonkey/types';
Make sure the .d.ts file is included in your tsconfig.json.