create Queue class

Author: agyin3

DataStructures/Queue.js

@@ -0,0 +1,50 @@
+export default class Queue {
+  constructor() {
+    this.queue = [];
+    this.front = null;
+    this.rear = null;
+  }
+
+  enqueue(element) {
+    this.queue.push(element);
+    this.rear = element;
+    this.front = this.queue[0];
+  }
+
+  dequeue() {
+    if (this.queue.length > 0) {
+      if (this.queue.length === 1) {
+        this.front = null;
+      } else {
+        this.front = this.queue[this.queue.length - 2];
+      }
+      return this.queue.shift();
+    } else {
+      throw new Error("Queue Underflow Exception: The queue is empty.");
+    }
+  }
+
+  getFront() {
+    if (this.queue.length === 0) {
+      return null;
+    }
+
+    return this.front;
+  }
+
+  getRear() {
+    if (this.queue.length === 0) {
+      return null;
+    }
+
+    return this.Rear;
+  }
+
+  size() {
+    return this.queue.length;
+  }
+
+  isEmpty() {
+    return this.queue.length === 0;
+  }
+}