There is a difference between the hashes generated from the opList and the commonObj objects in the Node.js and the front-end environment. This example is supposed to allow anyone to preview the difference.
This repository is supposed to be a resource for an issue that will be opened for the PDF.js library.
Running the Front-end example should be straightforward, just open the HTML and inspect the console output.
cd back-end
npm install
node pdf-testing.js
And observe the console output.