I've tried a few different techniques to use jsReport.use(require('jsreport-pdf-utils')()) to add in the pdfUtils and get access to appending, but anytime I try to append I get the following:

Error while executing pdf-utils operations. The first argument must be of type string or an instance of Buffer, ArrayBuffer, or Array or an Array-like Object. Received null

or

jsRender.pdfUtils.append shows cannot get append of undefined, which is the technique shown here: https://jsreport.net/learn/pdf-utils

What is the correct way to generate 2 pdf's and merge them?