ES Modules for service workers ('module' type option)

Category: Service Worker
Type: New or changed feature
Status: Enabled by default (Chrome 91)
Intent stage: Start prototyping

Summary

JavaScript will support modules in service 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.

Motivation

With this feature, web developers can more easily write programs in a composable way and share them among a page and workers.

Standards & signals

Specification: https://w3c.github.io/ServiceWorker/#service-worker-concept
Firefox: Closed Without a Position — https://bugzilla.mozilla.org/show_bug.cgi?id=1360870
Safari: Positive
Web developers: Positive
Tracking bug: https://bugs.chromium.org/p/chromium/issues/detail?id=824647

Docs: https://docs.google.com/document/d/1SeQ085YdBTtW3D_ygSpO0Wz2DAe8QiS1gj37IG5lstg/edit#

Explainers: https://github.com/w3c/ServiceWorker/commit/6d9500e99e764c12b117c63d10107e094d243662

View on chromestatus.com