TypeError: Cannot read properties of null (reading 'toUpperCase')

capricorn86 / happy-dom

A JavaScript implementation of a web browser without its graphical user interface

MIT License

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TypeError: Cannot read properties of null (reading 'toUpperCase') #1476

Open alexfict opened 2 days ago

alexfict commented 2 days ago

Describe the bug I am using happy-dom in my tests in combination with vitest and testing-library/vue to test vue components. When updating to happy-dom v13 I start getting the following error. It does not help to update to latest version.

The problem occurs in a custom web component.

I appreciate any tips to face this issue. Thank you!