N-API Addons for Node: Move Hot Loops Off the Event Loop

// scripts/bench-hotpath.ts
import { performance } from "node:perf_hooks";
import { parseJs } from "../src/parse-js.js";
import { parseNative } from "../src/parse-native.js";

const payload = Buffer.alloc(64 * 1024, 7);

function bench(fn: (b: Buffer) => number, label: string) {
 const t0 = performance.now();
 let sink = 0;
 for (let i = 0; i < 2_000; i++) sink ^= fn(payload);
 console.log(label, (performance.now() - t0).toFixed(1), "ms", sink);
}

bench(parseJs, "js");
try { bench(parseNative, "native"); } catch { console.log("native unavailable"); }

// ❌ Rewriting business logic in C++ because "Node is slow"
// Keep orchestration, I/O, and auth in JS — only move proven loops.

// src/crc.ts
let native: { crc32: (b: Buffer) => number } | null = null;
try {
 native = require("../build/Release/crc_fast.node");
} catch {
 native = null; // ✅ Lambda arm64 without prebuild still boots
}

export function crc32(buf: Buffer): number {
 if (native) return native.crc32(buf);
 let c = 0xffffffff;
 for (let i = 0; i < buf.length; i++) {
 c ^= buf[i];
 for (let k = 0; k < 8; k++) c = (c >>> 1) ^ (0xedb88320 & -(c & 1));
 }
 return (c ^ 0xffffffff) >>> 0;
}

// native/crc_fast.cc (node-addon-api sketch)
#include <napi.h>
#include <zlib.h>
Napi::Value Crc32(const Napi::CallbackInfo& info) {
 auto env = info.Env();
 auto buf = info[0].As<Napi::Buffer<uint8_t>>();
 // ✅ Sync only when < ~1ms; else AsyncWorker
 uLong crc = crc32(0L, Z_NULL, 0);
 crc = crc32(crc, buf.Data(), buf.Length());
 return Napi::Number::New(env, static_cast<double>(crc));
}
NODE_API_MODULE(crc_fast, [](Napi::Env env, Napi::Object exports) {
 exports.Set("crc32", Napi::Function::New(env, Crc32));
 return exports;
})