Queues and Stacks. They are abstract data structures that store values in a collection, whose utility is in the fact that these values can be added or extracted.
The difference between a queue and a stack is the order of fetching an element from the data structure.

• Stack. Your data is stored in column form, that is, the data added last at the top of this column is the one that can be removed.
  stack image.  Methods used: 
  • push(): adding the data
  • pop(): removing data

<script type="text/javascript">
  const mystack = [];
  console.log('Adding John'+mystack.push('John'));
  console.log('Adding Albert'+mystack.push('Albert'));
   console.log('Adding Robert'+mystack.push('Robert'));
  console.log(mystack.length);//3
  console.log(mystack.pop());//['Robert']
  console.log(mystack);//['John', 'Albert']
</script>   

[Robert→Albert→John]

• Queue. The data is stored in the form of a column, adding the data in the initial part, and being able to withdraw the data only from the final part of the column.
  tail image. Methods used:
  • push(): adding the data
  • shift(): removing data

<script type="text/javascript">
  const myqueue = [];
  console.log(myqueue.push('John'));
  console.log(myqueue.push('Albert'));
  console.log(myqueue.push('Robert'));
  console.log(myqueue);// ['John', 'Albert', 'Robert']
  console.log(myqueue[0]);//John
  console.log(myqueue[myqueue.length-1]);//Robert
  console.log(myqueue.shift());//Deleted John
  console.log(myqueue);//['Albert', 'Robert']
</script>