Thread like context for Node.js (using async_hooks)

node_thread.js

const asyncHooks = require('async_hooks');

const asyncMap = {}
asyncHooks.createHook({
  init(asyncId, type, triggerAsyncId) {
		const parent = asyncHooks.executionAsyncId();
		// 親がスレッドに属していれば子も属す
		if (asyncMap[parent]) {
			asyncMap[asyncId] = asyncMap[parent];

		// そうでなければメインスレッドに所属
		} else {
			asyncMap[asyncId] = mainThread;
		}
  },
  destroy(asyncId) {
    delete(asyncMap[asyncId]);
  },
  promiseResolve(asyncId) {
    delete(asyncMap[asyncId]);
  },
}).enable();

class Thread {
	constructor(entryFunction, threadLabel) {
		this.entryFunction = entryFunction;
		this.label = threadLabel;
	}

	run() {
		const self = this;
		const args = arguments;
		return new Promise((resolve, reject) => {
			setImmediate(() => {
				asyncMap[asyncHooks.executionAsyncId()] = self;
				try {
					resolve(self.entryFunction(...args));
				} catch (e) {
					reject(e);
				}
			});
		});
	}
}

const mainThread = new Thread(null, 'MainThread');

function getCurrentThread() {
	const eid = asyncHooks.executionAsyncId();
	if (asyncMap[eid]) {
		return asyncMap[eid];
	}
	return mainThread;
}

//
// ここからは動作確認用のコード
//

function printAsyncId(label) {
	const cThread = getCurrentThread();
	process._rawDebug(`(${cThread.label})${label}: eid=${asyncHooks.executionAsyncId()} tid=${asyncHooks.triggerAsyncId()}`);
}

function delayPrint(delay) {
	printAsyncId('delayPrint start');
	return new Promise((resolve, reject) => {
		setTimeout(() => {
			printAsyncId('delayPrint on timeout');
			console.log(getCurrentThread().text);
			printAsyncId('delayPrint before resolve');
			resolve();
			//reject();
		}, delay);
	});
}

async function asyncFunction(text, delay) {
	printAsyncId('run start');
	getCurrentThread().text = text;
	await delayPrint(delay);
	printAsyncId('run end');
}

printAsyncId('Main-Start');
const threadA = (new Thread(asyncFunction, 'aaa-delayPrint')).run('aaaaa', 1500);
printAsyncId('Main-Middle1');
const threadB = (new Thread(asyncFunction, 'bbb-delayPrint')).run('bbbbb', 1000);
const threadC = (new Thread(console.log, 'console.log')).run('ccccc');
printAsyncId('Main-End');