feature: add data type queue

src/lib/Queue.ts

@@ -0,0 +1,94 @@
+export class Node<T> {
+  public value: T;
+  public next?: Node<T>
+  public prev?: Node<T>
+
+  constructor(value: T, next?: Node<T>, prev?: Node<T>) {
+    this.value = value;
+    this.next = next;
+    this.prev = prev;
+  }
+}
+
+export class Queue<T> {
+  private _head?: Node<T>;
+  private _tail?: Node<T>;
+  private _size: number;
+
+  constructor() {
+    this._head = undefined;
+    this._tail = undefined;
+    this._size = 0;
+  }
+
+  public enqueue(data: T): void {
+    const node = new Node(data);
+
+    if (this._head === undefined) {
+      this._head = node;
+      this._tail = node;
+    } else {
+      this._tail!.next = node;
+      node.prev = this._tail;
+      this._tail = node;
+    }
+
+    this._size++;
+  }
+
+  public dequeue(): T | undefined {
+    const node = this._head;
+    if (node === undefined) return undefined;
+
+    this._head = this._head!.next;
+    this._head!.prev = undefined;
+    this._size--;
+
+    return node.value;
+  }
+
+  public clear(): void {
+    this._head = undefined;
+    this._tail = undefined;
+    this._size = 0;
+  }
+
+  public peek(): T | undefined {
+    if (this._head === undefined) return undefined;
+    return this._head.value;
+  }
+
+  public size(): number {
+    return this._size;
+  }
+
+  public toArray(): T[] | undefined {
+    if (this._size === 0) return undefined;
+
+    const array: T[] = [];
+    let currentNode: Node<T> = this._head!;
+    for (let i = 0; i < this._size; i++) {
+      if (currentNode.value !== undefined)
+        array.push(currentNode.value);
+
+      currentNode = currentNode.next!;
+    }
+    return array;
+  }
+
+  [Symbol.iterator](): Iterator<T> {
+    let currentNode = this._head;
+
+    return {
+      next(): IteratorResult<T> {
+        if (currentNode === undefined) {
+          return { value: undefined, done: true }
+        } else {
+          const data = currentNode.value;
+          currentNode = currentNode.next;
+          return { value: data, done: false }
+        }
+      }
+    }
+  }
+}