How to implement a Stack in JavaScript

function Stack() {
  this.top = null;
  this.size = 0;
}
function Node(data) {
  this.data = data;
  this.next = null;
}
Stack.prototype.push = function(data) {
    const node = new Node(data);
    node.next = this.top;
    this.top = node;
    this.size++;
};
Stack.prototype.pop = function() {
    if (this.top === null) return;
    const data = this.top.data;
    this.top = this.top.next;
    this.size = Math.max(0, this.size - 1);
    return data;
};
Stack.prototype.peek = function() {
  if (!this.top) return;
  return this.top.data;
};
Stack.prototype.isEmpty = function() {
  return this.size === 0 && !this.top;
};