update: queue using stack

Author: ashokdey

src/_DataStructures_/Queue/queue-using-stack/index.js

@@ -0,0 +1,28 @@
+const Stack = require('../../Stack');
+
+class Queue {
+  constructor() {
+    this.queue = new Stack();
+    this.temp = new Stack();
+  }
+
+  enqueue(data) {
+    this.queue.push(data);
+  }
+
+  dequeue() {
+    if (!this.queue.peek()) {
+      return null;
+    }
+
+    // pop all the element to the temp stack
+    while (this.queue.peek()) this.temp.push(this.queue.pop());
+    const el = this.temp.pop();
+
+    // push all the temp items to the queue again
+    while (this.temp.peek()) this.queue.push(this.temp.pop());
+    return el;
+  }
+}
+
+module.exports = Queue;