fix: prompt for update logic

[userquin]

With current version multiple clients get auto updated once the service worker receives the first update: with logic included on PR #394

With current changes, it is working properly, also tested on Firefox.

There are a few combinations using isUpdate and isExternal: these 2 flags from workbox-window are defined as boolean | undefined, when installed|activated events fired, undefined values have special meaning.

As an example, with only one client:

• on first visit we receive isExternal: false with no isUpdate
• on update, we receive isExternal: false and isUpdate: true and showSkipWaitingPrompt being called from waiting event.

Problems comes when we have a few clients, for example, 2 tabs in first browser instance and another browser instance:

On first visit we receive isExternal: false with no isUpdate only in the first one client visiting the app, other clients will not receive the event

On update it is more complex, since we can have a few combinations, here the tests I've made with previous setup (building between tests):

Test 1:
Reloading app in tab1:

• tab 1 receives isExternal: false and isUpdate: true
• tab 2 receives isExternal: false with no isUpdate
• second instance receives isExternal: false with no isUpdate

Click prompt reload button from tab1, all clients being updated, then build again.

Test 2:
Reloading browser instance 2:

• tab 1 receives isExternal: false and isUpdate: true
• tab 2 receives isExternal: false and isUpdate: true
• second instance receives isExternal: false and isUpdate: true

Click prompt reload button from browser instance 2, all clients being updated, then build again.

Test 3:
Reloading browser instance 2:

• tab 1 receives isExternal: false with no isUpdate
• tab 2 receives isExternal: false with no isUpdate
• second instance receives isExternal: false and isUpdate: true

Click prompt reload button from tab2 in browser instance 1, all clients being updated.

It seems on next update isExternal depends on the client that fires previous update.

[netlify]

✅ Deploy Preview for vite-plugin-pwa-legacy ready!

Name	Link
🔨 Latest commit	74bdc8e
🔍 Latest deploy log	https://app.netlify.com/sites/vite-plugin-pwa-legacy/deploys/639df4979b4dc2000806f342
😎 Deploy Preview	https://deploy-preview-428--vite-plugin-pwa-legacy.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site settings.

[userquin]

don't merge yet, I'm checking if we can switch event listener from installed to activated.

EDIT: I'll keep installed event (the PR ready)

[crunchwrap89]

Master @antfu can you please review this PR? <3