There's no shadowroot usage or customElement definitions here - what part of this is a web component? Not to trivialize the creation of what looks like a decent spreadsheet library, but this just looks like a standard library, not a web component.

Before there were Web Components, people made reusable web components.

But, probably good to disambiguate

this is awesome. One feature I'd like is the frozen column of airtable:

https://support.airtable.com/hc/en-us/articles/203312065-Cha...

Airtable has a lot of delights like this. Uncluttered nearly zero visual weight features. Thx for sharing that link.