cpp_to_javascript.md

DIY Node.js

Prereq

• I'm assuming you know how JavaScript works: Single-Threaded, Async, the EventLoop, and the Event Queue

Node Internals

• NodeJS is made of 3 different components:
  • A threading lib: LibUV
  • A JS Engine: V8
  • Some C++ code
• V8, SpiderMoney, and JavaScript Core are all JS engines
• global vars like console.log, setInterval, and setTimeout must be provided by NodeJS; not V8. They are written in C++, and our JS code interops with C++ via V8.
• NodeJS is like an interpretter, but it parses bits of JS and executes it in V8. It extends V8, but does not actually parse JS code.
• V8 has a default implementation of an eventloop, and different implementors can extend it.

Shallow Dive into LibUV

• Source
• Node uses libuc in order to do async threading in C.
  • Async funcs
  • Threads
  • Timers
  • Child Processes
  • Event Loops
• JS may be single-threaded, but Node's main thread should not be blocked by JS execution.
• The main thread offloads jobs to libuv, and libuv assigns the task to a worker in its threadpool. When tasks are done, they sync-up back to the main thread.

Tutorial

• follow along here.

How is Dino different from Node

• The foundational talk that launched Dino was the founder expressing regrets.
• For starters, Rust instead of C++. Tokio instead of LibUV (mostly for Rust compatibility.)
• Security: JS is a clean, fast (-er than python), and SANDBOX'd dynamic lang. Node breaks this by giving programs access to any/all OS calls.
• The Deno process has 1 entry & rebound point into V8 via protobufs. Makes the internal lbrary cleaner.
• Package management a bit different.