Incorrect TS Typings In Service Worker

[greyscaled]

Context

At the time of this writing, our service worker is very simple:

/* eslint-disable @typescript-eslint/no-explicit-any */

self.addEventListener("install", () => {
  console.log("[Service Worker] installed")
})

self.addEventListener("activate", (event: any) => {
  event.waitUntil((self as any).clients.claim())
  console.log("[Service Worker] activated")
})

self.addEventListener("fetch", () => {
  // Without this event handler we won't be recognized as a PWA.
})

However, with #2760 and any future/related efforts, the service worker will be growing in complexity and scope, as offline cached responses will be added.

Problem

Our service worker uses the same tsconfig as the rest of the project, and uses the any typing. What this amounts to are the following:

• Perceived access to APIs that do not exist in the context of a service worker (lib.d.ts)
• Lack of type safety on service worker, web worker global scope

Ideal Solution

Use a root, extendable tsconfig and separate tsconfig for the separate areas of the application - service worker, browser and node

Quick Solution

• Use triple slash directives to remove lib.d.ts and add in the missing references

See Also

• https://www.typescriptlang.org/docs/handbook/triple-slash-directives.html
• https://github.com/microsoft/TypeScript/blob/master/lib/lib.webworker.d.ts

[jsjoeio]

Yeah the ideal solution would be fantastic if it works out. These issues may also help as a reference:

• Specifying lib: DOM and WebWorker should not be mutually exclusive microsoft/TypeScript#20595
• Unable to access ServiceWorkerGlobalScope via self. microsoft/TypeScript#14877

[greyscaled]

@jsjoeio - I'll promise this one for the first milestone in June (see #2760 )

[jsjoeio]

Moving to v3.9.5 since we're planning to cut v3.9.4 sooner than June.

[stale]

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