Learning Manifest V3

At long last it's time to get serious about Manifest V3:

https://developer.chrome.com/extensions/migrating_to_manifest_v3

https://developer.chrome.com/extensions/migrating_to_service_workers

The Show So Far

✅ Canary Setup
If you're like me, you a) dislike the taste of coal dust and therefore b) have never even tried Chrome Canary.

⚠️ Episode One: Initializing Some Things and our First Nasty Surprise
Well ... crap. There's an Errors button in the UI bar.

✅ Episode Two: Permission to Run
Site permissions and API permissions are now two distinct things.

💩 Episode Three: Browser Button and Default Pop-Up
'action' requires trunk channel or newer, but this is the canary channel

⚠️ Episode Four: ~~Executing Scripts~~ Service Workers
This episode started off being about executing content scripts, but we have to deal with service workers first.

✅ Episode Five: Context Menus
The old-school inline onclick handler won't do, because our service worker is not a persistent background script.

⚠️ Episode Six: Convert Any Image URL to Data
This is hairy. Manifest V3 has no DOM in the background, so no more drawing to canvas after img.onload.

• Updated: this may be a bug. Here's Testing Cross-Origin Fetch from Service Workers, to help figure it out.)
• Another update: this looks like it may be a service worker problem, not a Manifest V3 problem. Inconsistent Fetch API Behavior has details.

✅ Episode Seven: The Persistence of Memory
Local storage will encourage smarter coding and better awareness of how some global events and systems behave.