Preact and Module not found: Can't resolve 'fs'

[IRediTOTO]

Hi, I got this error with Next. I found the answer on Google and fixed by moved my function to a new file.
I think this error come from Preact, staring use it? Because my other repo use same structure too and no issue (I put all func in to one file :D)

I want to ask: put all func into one file will make bundle BIGGER, right? Just wonder...