reads and displays stdin line by line without using @@asyncIterator

delayed-cat.js

const rl = require('readline').createInterface({ input: process.stdin });

const first = { promise: Promise.resolve(), next: null };
const queue = [first];
function asyncReadLine(event, asyncCallback){
  rl.on(event, async (...args) => {
    queue.push({ promise: new Promise(resolve => void (queue[queue.length - 1].next = resolve)), next: null });
    const promiseObj = queue.shift();
    await promiseObj.promise;
    await asyncCallback(...args);
    promiseObj.next();
  });
}
asyncReadLine('line', async line => {
  await new Promise(res => setTimeout(() => res(), 1000)); // delaying 1s to confirm whether inputs are sequentially read.
  console.log(line);
});