Implemented a stack algorithm in vanilla js

data_structures/stacks/stack.js

@@ -0,0 +1,53 @@
+// Author: Austin Crane
+// this is a node program, you can run this with node stack.js
+
+// Stack simple stack implementation
+// accessed via a "private" items array
+function Stack() {
+  this._items = [];
+  return this;
+}
+
+// push adds an item onto the stack
+Stack.prototype.push = function(n) {
+  this._items.push(n);
+}
+
+// pop removes the item on the top of the stack
+Stack.prototype.pop = function() {
+  if (this.size() === 0) {
+    // if your trying to access an empty stack that
+    // would be considered an error
+    console.error('reached end of stack');
+    return;
+  }
+  return this._items.pop();
+}
+
+// size gives the size of the stack
+Stack.prototype.size = function() {
+  return this._items.length;
+}
+
+// simple "main" program to work with a stack
+function stackExample() {
+  var s = new Stack()
+  s.push(1);
+  s.push(2);
+  s.push(3);
+
+  // print size of stack
+  console.log(s.size());
+
+  // 3
+  console.log(s.pop());
+  // 2
+  console.log(s.pop());
+  // 1
+  console.log(s.pop());
+
+  // this will log an error reach end of stack
+  console.log(s.pop());
+}
+
+stackExample();