lmiller1990 / node-addon-learning

Practice repo for Node Addon API / C++

Node Addon API

I am learning about C++ via studying Node.js, v8 and learning to write some addons.

I found out there are many ways to talk to v8 / Node.js via C++:

1. v8 APIs
2. nan
3. Node API
4. Node Addon API

Each one builds on the previous layer.

I learned some basic things like sending data back and forth between JavaScript running in Node.js and C++. I'm trying to find out how to the equivalent in C++ of the following JS:

const path = require('path')
const { Greet } = require("./greeter");
const greet = new Greet(name);
greet.greet();

I looked at some examples which were pretty useful, but there is a few things I couldn't figure out the correct syntax for in C++ using Node Addon API, namely:

1. can I require or get a handle on a JS module from userland?
2. how about accessing Node.js APIs in C++? Can I access path, vm, fs etc?
3. creating a new instance of a class / function? Is this something I can do in C++?
4. calling a method on an object? eg const path = require('path'); path.join(...)? Can I do this using a C++ API?

I understanding "writing JS in C++" isn't really the point of the Addon API, but I'm still interested in how I might accomplish something like this. Is Node Addon API / Node API the right abstraction? Or do I need to use nan (much lower level than I'm currently comfortable with, but I'm learning fast!)

Someone shared with me one example doing something sort of similar. This user (Chinese article, I used Google Translate to read it) is doing something like this using C++ (via Rust). He uses the vm module to create a new Script instance and calls a method on it - so it seems this is possible in some fashion? That user is doing it for security purposes, which is a pretty neat use case.

He says he does the following equivalent in Rust - he also says "the original Rust code is too long to post" - maybe this is more complex than I'm expecting.

const vm = require('vm');

const script = vm.Script(dummyCode, {
  cachedData, // 这个就是字节码
  filename,
  lineOffset: 0,
  displayErrors: true
});

script.runInThisContext({
  filename,
  lineOffset: 0,
  columnOffset: 0,
  displayErrors: true
});

Running

npm install
node-gyp build
node src/binding.js