I\'ve looked around and it seems like several people are having this issue but no-one seems to have solved it:
Adding Apple in-app purchase to Electron HTML/JS app
In addition to user108828 i can suggest a couple more ideas to solve your problem:
You can implement MAS receipt validation as a dynamic library in obj-C/C++/C using Xcode and then include it in your project via ToTallNate's node-ffi. For implementation you can use any of a large number of solutions that you can easely find on web.
Another way to perform receipt verification is to create a self made node addon that includes openssl and objective-c runtime libraries. For this solution you may also need to include CoreFoundation and/or some other apple frameworks. As a result you will be able to implement your validation in pure C/C++ and incapsulate it in your node module.
The API design of your dylib/node addon is strictly up to you and should be kept in secret.
Good luck!