Gatsby site failed to deploy

Hey Netlify team,

I am trying to deploy my personal website using Gatsby, but it is failng to deploy.
It is working fine in my local environment. I have worked my way through fixing the
issue from the first failed deploy however this one I am having more trouble with.
Gatsby has a lot going on which I am not too familiar with. The main issue looks like
a TypeError in createPages.js from the Deploy log below. Any suggestions on what I
could do to fix the issue and have a successful deployment would be great.

Thanks in advance,

The problem appears to be discussed here: