nestedWhileLoop.js

// nested Loop

.then(() => {
  var heaplist = 4;
  const whileHeapList = () => {
    if (heaplist) {
      heaplist--;
      var i = 0;
      var j = 5;
      const innerWhileLoop = () => {
        if (i <= j) {
          i++;
          new Promise(innerWhileLoop);
        } else {
          new Promise.resolve();
        }
      }
      // first iteration of innerWhileLoop
      new Promise(innerWhileLoop);
      // Continue looping with whileHeapList
      new Promise(whileHeapList);
    }
    return new Promise.resolve();
  }
  // first iteration of whileHeapList
  return new Promise(whileHeapList);
});

tests.js

// Sinlge Loop

.then(() => {
  var heaplist = 4;
  const whileHeapList = () => {
    if (heaplist) {
      heaplist--;
      return new Promise(whileHeapList);
    }
    return new Promise.resolve();
  }
  return new Promise(whileHeapList);
});