A simple example using linear data structures of Stacks and Queues in Javascript.

StacksAndQueues.js

function Stack() {
  this._size = 0;
  this._storage = {};
}

Stack.prototype.push = function(data) {
  this._size += 1;
  this._storage[this._size] = data;
};

Stack.prototype.pop = function() {
  let size = this._size;
  if (size) { 
    const deletedData = this._storage[size];
    delete this._storage[size];
    this._size -= 1;
    return deletedData;
  }
};


function Queue() {
  this._storage =  {};
  this._oldestIndex = 1;
  this._newestIndex = 1;
}

Queue.prototype.size = function() {
  return this._newestIndex - this._oldestIndex;
};

Queue.prototype.enqueue = function(data) {
  this._storage[this._newestIndex] = data;
  this._newestIndex += 1;
};

Queue.prototype.dequeue = function() {
  let oldestIndex = this._oldestIndex;
  let newestIndex = this._newestIndex;
  if ( oldestIndex !== newestIndex ) {
    const deletedData = this._storage[oldestIndex];
    delete this._storage[oldestIndex];
    this._oldestIndex += 1;
    return deletedData;
  }
};