[nodejs][worker_threads][es2018] req/res to Worker with for-await loop of ES2018

main.js

// node.js worker_threads module example with for-await loop: main thread side
//$ node --exprimental-worker main.js
const path = require("path");
const {Worker, MessageChannel} = require("worker_threads");

// async queue as "asyncIterator" in ES2018
class Queue {
    constructor() {
        this.polls = [];
        this.gets = [];
    }
    [Symbol.asyncIterator]() {return this;}
    next() {
        return new Promise(res => {
            if (this.polls.length > 0) this.polls.shift()(res);
            else this.gets.push(res);
        });
    }
    poll() {
        return new Promise(res => {
            if (this.gets.length > 0) res(this.gets.shift());
            else this.polls.push(res);
        });
    }

    // enqueue as iterator next objects
    post(value) {
        return this.poll().then(get => get({value, done: false}));
    }
    close() {
        return this.poll().then(get => get({done: true}));
    }
}

async function* send(worker, data) {
    const mc = new MessageChannel();

    // port1 as asyncIterator queue
    const queue = new Queue();
    mc.port1.on("message", ({data}) => queue.post(data));
    mc.port1.on("close", () => queue.close());

    const ports = [mc.port2];
    worker.postMessage({data, ports}, ports);
    yield* queue;
    //for async (const v of queue) yield v; // same as yield* in async gen
}

// main
(async function main() {
    const w = new Worker(path.resolve(__dirname, "./worker.js"));
    for await (const chunk of send(w, "Hello ES2018 World")) {
        console.log(chunk);
    }
    w.terminate();
})().catch(console.error);

worker.js

// node.js worker_threads example: worker side code
// NOTE: in main, parentPort is null
const {parentPort} = require("worker_threads");

// As DOM MessageEvent style parameters
parentPort.on("message", ({data, ports}) => {
    // echo response also as a MessageEvent like
    for (const chunk of data.split(/\s+/)) {
        ports[0].postMessage({data: chunk, ports: []});
    }
    ports[0].close();
});