fix: added the queue interface

Author: co-bby

data_structures/array_queue.ts

@@ -4,7 +4,14 @@
  * It means that the first element that was added to the queue will be the first one to be removed.
  * The time complexity of the operations is O(n).
  */
-export class ArrayQueue<T> {
+interface Queue<T> {
+    enqueue(item: T): void
+    dequeue(): T | undefined
+    peek(): T | undefined | null
+    isEmpty(): boolean
+
+}
+export class ArrayQueue<T> implements Queue<T>{
     private queue: T[] = [];
 
     /**
@@ -53,7 +60,7 @@ export class ArrayQueue<T> {
      *
      * @returns The item at the front of the queue or null if the queue is empty.
      */
-    front(): T | null {
+    peek(): T | null {
         if (this.isEmpty()) {
             return null;
         }

data_structures/linkedlist_queue.ts

@@ -14,13 +14,23 @@
 
 */
 
+export interface Queue<T> {
+    enqueue(item: T): void
+    dequeue(): T | undefined
+    peek(): T | undefined | null
+    isEmpty(): boolean
+
+}
+
 type Node<T> = {
     value: T,
     next?: Node<T>,
 }
 
 
-export class LinkedQueue<T> {
+
+
+export class LinkedQueue<T> implements Queue<T> {
 
     public length: number;
     public head?: Node<T>;
@@ -46,7 +56,7 @@ export class LinkedQueue<T> {
 
     }
     // Remove elements to the front/head of the Queue
-    deque(): T | undefined {
+    dequeue(): T | undefined {
 
         // If there is no head return undefined
         if (!this.head) {

data_structures/test/array_queue.test.ts

@@ -24,13 +24,13 @@ describe("Testing Queue data structure", () => {
         const queue = new ArrayQueue<number>();
         queue.enqueue(1);
 
-        expect(queue.front()).toBe(1);
+        expect(queue.peek()).toBe(1);
     });
 
     it("front should return null when the queue is empty", () => {
         const queue = new ArrayQueue<number>();
 
-        expect(queue.front()).toBe(null);
+        expect(queue.peek()).toBe(null);
     });
 
     it("length should return the number of elements in the queue", () => {