Service worker: caching is slow with big assets

Issue #19733696 • Assigned to wwatri


Roberto S.
Nov 27, 2018
This issue is public.
Found in
  • Microsoft Edge
Found in build #
Reported by 5 people

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Steps to reproduce

Using service worker breaks the web app on Edge browser for desktop the first time it is loaded.

The problem seems the pre-caching of static files during the Service Worker’s install phase.

In my app I have 15 chunks and a lot of assets totaling around 15 MB, and I’m using a prefetch strategy. This is not a problem for other browsers, but apparently it’s a problem for Edge. And while it tries to cache them, the app is busy (and i.e. it does not perform external http requests).

Here you can find a my app in production:


  • Open Edge browser for desktop
  • Clean the browser cache (important!) and restart the browser
  • Go to
  • Tap Get started
  • Type a location & tap Search

Nothing happens: after 60 seconds you will get an error (it is a timeout)

Alternatively, you can try to refresh the page: it will take a while, even a few minutes: after which the app will start working correctly.

N.B. In the next hours, I’ll trying to improve performance by reducing assets, and by adopting a lazy strategy, at least to allow the app to work.


Windows 10 Pro v1803
Intel® Core™ i7-8650U CPU 1.GHz 2.11 GHz
RAM 16,0 GB

Connection speed: 4.77 Mbps


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    Comments and activity

    • Microsoft Edge Team

      Changed Assigned To to “wwatri”

    • Update

      As I said above, I reduced the size of static assets to around 4 MB and adopted a lazy strategy. Now the app works, but the problem still exists.


      • Clean the browser cache
      • Go to the app
      • Try to refresh the page

      With a connection of about 5 Mbps, it takes even one minute to load.

    • I have the same problem also on 18.17763

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