JavaScript will support modules in shared workers. Setting 'module' type by the constructor's type attribute, worker scripts are loaded as ES modules and the import statement is available on worker contexts.
With this feature, web developers can more easily write programs in a composable way and share them among a page and workers.
Docs: https://docs.google.com/document/d/1sSdYdSOLd5zvnNGeVNlBqfTZs_VRPIrrigV3SlMnWjg/edit?usp=sharing
Explainers: https://html.spec.whatwg.org/multipage/workers.html#shared-workers-and-the-sharedworker-interface