Description

At this point, according to MDN: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script/type/importmap, Chrome, Firefox, Opera & Safari have added support for importmaps ONLY for main threads.

Since March 2018 there is an open ticket to also enable their support for Worker, SharedWorker & ServiceWorker without any progress: WICG/import-maps#2

For me, being the author of a JavaScript (off the main thread) multithreading framework: https://github.com/neomjs/neo, not having the support for the worker scope is a showstopper / blocker.

This mostly affects the micro frontends topic. Use case: An application worker loads apps & components which are specified as JS modules, using import statements. Right now it is impossible to use importmaps here (unless hacking a compile step in there to manually replace relative paths).

Now devs could create additional npm packages to create components or child-apps, which would import framework base-classes from a different path / folder. This can easily result in getting multiple versions of the same file. Not only problematic for file size, but has a potential to break things (imagine importing 2 different IdGenerator classes).

In case the app worker had an import map, all framework related imports would point to the same source of truth.

It would make a big impact and make a lot of devs who would like to create JavaScript code which runs without a build step very happy, in case this feature was in place.

Thanks a lot!
Tobias

Specification

https://github.com/WICG/import-maps

Additional Signals

No response