How to run a function located in an html file if the project is built with webpack?

Question

webpack

Hello. Tell me please. There is a project created in html, css, js, built by webpack. Everything was great, everything worked until my boss took it into his head to put all the calls to the self-written functions used in html files. And now nothing works for me.
I have a feeling that webpack doesn't bundle them into a single js file. What will we do?