[thenaturalist]

Asking as a self-taught not-so-advanced-yet guy wanting to build a similar I/O web app: Could you elaborate a bit on how client-side transformation/ generation could be achieved?

[mypalmike]

Perhaps using http://pdfkit.org/

[escap]

or using https://github.com/bpampuch/pdfmake e.g. http://pdfmake.org/playground.html "pdfmake is based on a truly amazing library pdfkit.org"

[kranner]

There's also https://github.com/MrRio/jsPDF