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JavaScript modules in service workers

Newly Available (since 2026-01-13)
Expected to be Widely Available on 2028-07-13

The navigator.serviceWorker.register() method accepts { type: "module" } to load scripts that use import and export. Also known as ECMAScript modules or ESM in service workers.

Browser support

  • Chrome 91 Released on 2021-05-25
  • Chrome Android 91 Released on 2021-05-25
  • Edge 91 Released on 2021-05-27
  • Firefox 147 Released on 2026-01-13
  • Firefox for Android 147 Released on 2026-01-13
  • Safari 15 Released on 2021-09-20
  • Safari on iOS 15 Released on 2021-09-20

MDN documentation

Specifications

Web Platform Tests (WPT)

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