20

I created a new project with create-react-app then ran npm start then this showed up. https://imgur.com/a/3By9NCr

Using FF 69.0.3

Anurag Srivastava
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Dwyte
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5 Answers5

15

This problem seems to only happen in Firefox. Edge worked fine.

After creating the project, in index.js change:

serviceWorker.register();
//serviceWorker.unregister();

Still trying to figure whose fault this is, but this should get you going.

david.pfx
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  • this registers the serviceworker, which comes with a bunch of caveats https://create-react-app.dev/docs/making-a-progressive-web-app/#why-opt-in – tobbe Nov 21 '19 at 09:28
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    @tobbe: Indeed, but do you have an answer for why it happens and a better way to fix it? – david.pfx Nov 22 '19 at 12:55
7

Another solution found in the link in the answer by Niraj Niroula:

If you want to keep the Delete cookies and site data when Firefox is closed option enabled, click on the Manage Exceptions button and add localhost (with the protocol and port) to the exceptions list:

cookie and site data deletion exceptions

g-otn
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4

A lot of answers here do actually solve the issue but the simplest way I have found is to add npm package serve to your dependencies.

yarn add serve or npm i serve

and then replace your start script with the following:

"scripts": {
    "start": "serve -s build",
}

This is actually straight out of the create-react-app docs

Leo Policastro
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4

Seems that the issue exists only in Firefox. Anyone still bugged by this bug can try disabling Delete cookies and site data when Firefox is closed option in Privacy and Security settings. enter image description here Or try wrapping the navigator.serviceWorker usages inside a try/catch. In my case

  if ("serviceWorker" in navigator) {
    navigator.serviceWorker.ready
      .then(registration => {
        registration.unregister();
      })
      .catch(error => console.log("ServiceWorker Warning: ", error));
  }

For related discussion and more info

Niraj Niroula
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3

I had this error occur as well. Was able to clear it up by deleting the create-react-app serviceWorker.js file

Kory
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