# how to resolve invalid module

**URL:** <https://talk.observablehq.com/t/how-to-resolve-invalid-module/8239>\
**Category:** Help\
**Created:** [September 3, 2023, 2:28pm UTC](https://talk.observablehq.com/t/how-to-resolve-invalid-module/8239 "2023-09-03T14:28:44Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![alicialics](https://yyz2.discourse-cdn.com/flex030/user_avatar/talk.observablehq.com/alicialics/32/8010_2.png) [@alicialics](https://talk.observablehq.com/u/alicialics)\
**Post date:** [September 3, 2023, 2:28pm UTC](https://talk.observablehq.com/t/how-to-resolve-invalid-module/8239/1 "2023-09-03T14:28:44Z")

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I forked an existing [notebook](https://observablehq.com/d/6221036819e5975c) and updated versions to latest. However I am running into an issue invalid module.

One of the packages has a dependency seedrandom which relies on crypto. It’s possible to use a [minimal version](https://observablehq.com/@fil/seedrandom-minimal) of it but how do I do package resolutions on observable?

I also tried a es6 import and didn’t seem to work as well

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**Author:** ![Fil](https://yyz2.discourse-cdn.com/flex030/user_avatar/talk.observablehq.com/fil/32/207_2.png) [@Fil](https://talk.observablehq.com/u/Fil)\
**Post date:** [September 4, 2023, 10:28am UTC](https://talk.observablehq.com/t/how-to-resolve-invalid-module/8239/2 "2023-09-04T10:28:58Z")

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Hello, I have updated the original notebook [Hello tfjs-tsne / Fil | Observable](https://observablehq.com/@fil/hello-tfjs-tsne) with esm.sh.

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<div class="post-metadata">

**Author:** ![alicialics](https://yyz2.discourse-cdn.com/flex030/user_avatar/talk.observablehq.com/alicialics/32/8010_2.png) [@alicialics](https://talk.observablehq.com/u/alicialics)\
**Post date:** [September 4, 2023, 5:08pm UTC](https://talk.observablehq.com/t/how-to-resolve-invalid-module/8239/3 "2023-09-04T17:08:06Z")

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Hi @Fil thats awesome! can I ask why the [example](https://observablehq.com/d/6221036819e5975c) I have always have a error:

> coords = TypeError: Cannot read properties of null (reading ‘findBackend’)

Your example works fine and I have the same code as you in my notebook!

Edit, I rerun the example and the error went away… I guess it was using some kind of cache…