MV3: creating `new Worker` from the service worker?

[Juraj M.]

I have some compression + encoding job which can take 10+ seconds, so in MV2 I've used`new Worker(...)` to prevent freezing of my extension.

But it seems that Service worker doesn't have Worker: "ReferenceError: Worker is not defined".

What can I do?

[Robbi]

The service worker is a worker, so you will simply have to do these jobs within the SW.

If the job request starts from an extension page, you will have to send a message from that page to the SW requiring the execution of the jobs

[Juraj M.]

Thanks Robbi,

I guess I have no other choice now :(

It was already running in the background script, but having it in a worker would prevent background script from being stuck while the operation was running. Now when it starts, no other background operation can run.

I wish I could have more than one service worker. Or some quick WebAssembly versions of those slow libraries I use :).

Anyway, thanks!

[wOxxOm]

MV3 has broken this feature because service worker specification forbids starting a new nested worker, reported in https://crbug.com/1219164.

Doing such heavy encoding without creating a nested worker is a very bad idea because it'll freeze the service worker for the duration of the job, so it won't be able to react to `chrome` events/messages.

Until this bug is fixed, your options are:

• keep using MV2;
• open a new tab/window/popup and start the worker inside;
• add an extension iframe via web_accessible_resources to any web page, start the worker inside;
• a future workaround would be to use an offscreen document when and if it's implemented.

[Juraj M.]

Thanks!

Those are some crazy out of box thinking ideas! I have a mixed feelings about it.

I do hope the linked bug will be fixed, that's for sure the best solution. Thank you for sharing it!