Hello Kai Wang,
I have 2 answers which may help you.
> You can use obfuscation methods to make you code difficult to read and analyze, you also can use your own obfuscation logic.
> You can create your app in such a way it avoid specific mouse and keyboard event, that takes to dev tools using js.
Note: Any resources used for front end are always be seen using dev tools.
Hope my answer helps, waiting to hear from you.