How to edit the source to trap unhandled errors?

[jumpjack]

I have a very complex document which raises many errors which are not managed by docx2html, which just stops without any warning, for example:

..\docx4js\src\openxml\docx\document.js:9 Uncaught (in promise) TypeError: Cannot read property 'documentElement' of null
at document.parse (..\docx4js\src\openxml\document.js:28)
at document.parse (..\docx4js\src\openxml\docx\document.js:9)
at ..\src\index.js:6

I am a javascript developer, but not a Node.js developer, and usual methods that I use to debug a javascript code do not work for docx2html: opening console, looking at error messages, clicking on the referred .js files, examining them, putting linebreaks and using local overrides to make changes and test.
I would like to add some error messages any time docx2html crashes, to avoid crashing and to warn me next times. How can I do it?

In above error I see it is referred "..\docx4js\src\openxml\docx\document.js", which actually maps to "file:///C:/MYPATH/docx2html/dist/..\docx4js\src\openxml\docx\document.js"... but there is no "docx4js" folder in my installation of doc2xhtml, so where does the browser look for docx4js, and why aren't its source shown in "Sources" tab of Chrome?

[lalalic]

main file is specified in package.json, so you can use source map in your project. please try latest