friendly-pow VS iswasmfast

It kinda does? Here's the puzzle creator library: https://github.com/FriendlyCaptcha/friendly-pow

Yeah, WebAssembly have i64/u64 types as first class citizens unlike JavaScript which should emulate it or use BigInt which drastically slower than native 64-bit types. That's why crypto algorithms got a lot of speed benefits. AssemblyScript also show this. See this:

https://github.com/FriendlyCaptcha/friendly-pow

At a glance, the bindings for wasm copy the data,

https://github.com/zandaqo/iswasmfast/blob/54bbb7b539c127185...

If the running code is short enough then that copy might easily make the wasm version much slower. That is indeed a known downside of wasm (calls to JS are somewhat slow, and copying of data even more so - wasm shines when you can avoid those things).

If it's not that, then a 10x difference suggests you are running into some kind of a VM bug or limitation.

WASM has its moments, as you can see in this[1] benchmark it outperforms JS and native addons on certain tasks.

Since the bottleneck with native addons is usually data copying/marshalling, and we have direct access to WebAssembly memory from the JavaScript side, using WebAssembly on this "shared" memory might become the best approach for computationally heavy tasks. I wrote about it a bit here[2].

[1] https://github.com/zandaqo/iswasmfast

A few years ago I did similar comparison but in context of Node.js and sans manual optimizations: https://github.com/zandaqo/iswasmfast

In my work, I have come to conclusion that it seldom pays off to go "native" when working with Node.js. More often than not, rewriting some computationally heavy code in C and sticking it as a native module yielded marginally better results when compared with properly optimized js code. Though, that doesn't negate other advantages of using said technologies: predictable performance from the start and re-using existing code base.