How to have the language server in Visual Studio Code recognize that a JavaScript file is meant to be used as service worker?

Question

For example, given a single file service_worker.mjs with these contents:

self.addEventListener("install", () => self.skipWaiting());
self.addEventListener("activate", () => self.clients.claim());

In Visual Studio Code, skipWaiting and clients have red squiggly underlines as if there are syntax errors and show error messages when I hover over the words:

Property 'skipWaiting' does not exist on type 'Window & typeof globalThis'.

Property 'clients' does not exist on type 'Window & typeof globalThis'.

Normally that would be correct, but I would like to use that file as a service worker, so I think that self should be treated as ServiceWorkerGlobalScope by the language server. How do I get the language server in Visual Studio Code to recognize self as ServiceWorkerGlobalScope?

Screenshot of code and "problems" tab in Visual Studio Code:

• Sophia Abigail: I believe this should solve it! stackoverflow.com/questions/46493539/… ``` // Source - stackoverflow.com/a/50823389 // Posted by htho // Retrieved 2026年01月04日, License - CC BY-SA 4.0 { "compilerOptions": { "lib": [ "webworker" ] } } ```
• marching_person: @Sophia, thanks, that helped me understand the issue further, although that link is for Web Workers, which I think has a different API than Service Workers. I settled on this approach for now: const serviceWorker = /** @type {ServiceWorkerGlobalScope} */ (/** @type {unknown} */ (globalThis.self));.