async queue in javascript

queue.js

let count = 0;
let running = false;
const queue = {};

const addTask = task => {
  queue[count++] = task;
  if (running === false) runTasks();
}

const runTasks = async () => {
  running = true;
  for (let key = 0; key < count; key++) {
    const func = queue[key];
    delete queue[key];
    await func();
  } 
  running = false;
}


addTask(() => {  
  return new Promise(done =>
    setTimeout(() => {
      console.log(1);
      done();
    }, 1000)
  )
})

addTask(() => {
  console.log(2);
})

addTask(() => {  
  return new Promise(done =>
    setTimeout(() => {
      console.log(3);
      done();
    }, 1000)
  )
})

addTask(() => {
  console.log(4);
})