Create a whatsapp unsaved contacts extractor

I want a extractor software that can extract all my unsaved contacts of whatsapp and save them in a excel file and i want it with source code. You can refer to the tool below-

https://wa-contacts-extractor.watool.online/

This tool is able to extract only some contacts through whatsapp web beta i have more than 10k unsaved contacts and i want to extract all of them in an excel file.