fix: #89. Supports maxLen for max length of the Deque

src/data-structures/queue/deque.ts

@@ -32,8 +32,9 @@ export class Deque<E = any, R = any> extends IterableElementBase<E, R, Deque<E,
     super(options);
 
     if (options) {
-      const { bucketSize } = options;
+      const { bucketSize, maxLen } = options;
       if (typeof bucketSize === 'number') this._bucketSize = bucketSize;
+      if (typeof maxLen === 'number' && maxLen > 0 && maxLen % 1 === 0) this._maxLen = maxLen;
     }
 
     let _size: number;
@@ -73,6 +74,17 @@ export class Deque<E = any, R = any> extends IterableElementBase<E, R, Deque<E,
     return this._bucketSize;
   }
 
+  protected _maxLen: number = -1;
+
+  /**
+   * The maxLen function returns the max length of the deque.
+   *
+   * @return The max length of the deque
+   */
+  get maxLen() {
+    return this._maxLen;
+  }
+
   protected _bucketFirst = 0;
 
   /**
@@ -193,6 +205,7 @@ export class Deque<E = any, R = any> extends IterableElementBase<E, R, Deque<E,
     }
     this._size += 1;
     this._buckets[this._bucketLast][this._lastInBucket] = element;
+    if (this._maxLen > 0 && this._size > this._maxLen) this.shift();
     return true;
   }
 
@@ -257,6 +270,7 @@ export class Deque<E = any, R = any> extends IterableElementBase<E, R, Deque<E,
     }
     this._size += 1;
     this._buckets[this._bucketFirst][this._firstInBucket] = element;
+    if (this._maxLen > 0 && this._size > this._maxLen) this.pop();
     return true;
   }
 

src/data-structures/queue/queue.ts

@@ -100,7 +100,6 @@ export class Queue<E = any, R = any> extends IterableElementBase<E, R, Queue<E,
    *
    * The function "fromArray" creates a new Queue object from an array of elements.Creates a queue from an existing array.
    * @public
-   * @static
    * @param {E[]} elements - The "elements" parameter is an array of elements of type E.
    * @returns The method is returning a new instance of the Queue class, initialized with the elements from the input
    * array.

src/types/data-structures/queue/deque.ts

@@ -1,3 +1,6 @@
 import { IterableElementBaseOptions } from '../base';
 
-export type DequeOptions<E, R> = { bucketSize?: number } & IterableElementBaseOptions<E, R>;
+export type DequeOptions<E, R> = {
+  bucketSize?: number,
+  maxLen?: number
+} & IterableElementBaseOptions<E, R>;

test/unit/data-structures/queue/deque.test.ts

@@ -260,6 +260,25 @@ describe('Deque - Utility Operations', () => {
     // deque.print();
     // expect(consoleSpy).toHaveBeenCalledWith([1, 2]);
   });
+
+  test('should maxLen work well', () => {
+    const dequeMaxLen = new Deque([3, 4, 5, 6, 7], { maxLen: 3 });
+    expect(dequeMaxLen.size).toBe(3);
+    expect(dequeMaxLen.toArray()).toEqual([5, 6 ,7]);
+    dequeMaxLen.unshift(4);
+    dequeMaxLen.unshift(3);
+    expect(dequeMaxLen.size).toBe(3);
+    expect(dequeMaxLen.toArray()).toEqual([3, 4, 5]);
+
+    const dequeNoMaxLen = new Deque([3, 4, 5, 6, 7]);
+    expect(dequeNoMaxLen.size).toBe(5);
+    expect(dequeNoMaxLen.toArray()).toEqual([3, 4, 5, 6, 7]);
+    dequeNoMaxLen.unshift(4);
+    dequeNoMaxLen.unshift(3);
+    expect(dequeNoMaxLen.size).toBe(7);
+    expect(dequeNoMaxLen.toArray()).toEqual([3, 4, 3, 4, 5, 6, 7]);
+
+  });
 });
 
 describe('Deque - Additional Operations', () => {