I read the blog. And I tried the code as presented. It didn’t work either as it appears (based on the busboy README using an import isn’t supported.
Using busboy@0.3.1 the import seems to work when
import * as Busboy from 'busboy'
is changed to
import Busboy from 'busboy'
however the function times out (take more than 10 seconds) even with a 10kb image.
If you are planning to run ffmeg to transform images, keep in mind the execution time limit (which can get raised to 26 seconds on request.) Also worth reading are