Add Queue class with basic queue operations

JavaScript/data_structures/queue/queue.js

@@ -0,0 +1,48 @@
+class Queue {
+  constructor() {
+    this.items = [];
+  }
+
+  // Add element to rear
+  enqueue(element) {
+    this.items.push(element);
+  }
+
+  // Remove element from front
+  dequeue() {
+    if (this.isEmpty()) return "Underflow";
+    return this.items.shift();
+  }
+
+  // Get front element
+  peek() {
+    if (this.isEmpty()) return "No elements in Queue";
+    return this.items[0];
+  }
+
+  // Check if empty
+  isEmpty() {
+    return this.items.length === 0;
+  }
+
+  // Size of queue
+  size() {
+    return this.items.length;
+  }
+
+  // Display queue
+  print() {
+    console.log(this.items.join(" <- "));
+  }
+}
+
+// Example usage:
+const q = new Queue();
+q.enqueue(10);
+q.enqueue(20);
+q.enqueue(30);
+q.print();       // Output: 10 <- 20 <- 30
+console.log(q.dequeue()); // Output: 10
+console.log(q.peek());    // Output: 20
+console.log(q.size());    // Output: 2
+console.log(q.isEmpty()); // Output: false