Fix "Cannot convert undefined to a BigInt"

[KernelFreeze]

• I have verified my changes didn't break the example project.

Description

I fixed the following exception when executing queries:

Uncaught (in promise) TypeError: Cannot convert undefined to a BigInt
  insertId: results.lastRowId !== null ? BigInt(results.lastRowId) : undefined,
                                         ^
      at executeQuery

[aidenwallis]

Is this documented in cloudflare's docs anywhere, do you have a link to it? If so, lets insert a comment?

I'm also concerned about other zero values here, hence the explicit check

[KernelFreeze]

It's not documented sadly, but I get a lot of undefineds. I added a new commit that returns the original variable so things like 0 and NaN get returned as is.

[aidenwallis]

🤔 Now I'm wondering if 0 should really be BigInt(0) here lol, perhaps results.lastRowId === undefined || results.lastRowId === null ? undefined : BigInt(results.lastRowId)

there is a difference between those two and we should aim to return the correct types

Edit: yep looks like this generates type errors, check the build 👍

[KernelFreeze]

Is it ok like this?

[aidenwallis]

These changes all make sense to me now, thank you for the contribution!