Unsolved problem from this leetcode problem: https://leetcode.com/problems/design-circular-queue/submissions/

unsolvedCircularQueue.js

/**
 * @param {number} k
 */
var MyCircularQueue = function(k) {
    this.arr = new Array(k);
    this.headCount = 0;
    this.tailCount = 0;
};

/** 
 * @param {number} value
 * @return {boolean}
 */
MyCircularQueue.prototype.enQueue = function(value) {
    
    if (this.tailCount > this.arr.length-1) return false;
    
    this.arr[this.tailCount] = value;
    this.tailCount+=1;
    
    return true;
};

/**
 * @return {boolean}
 */
MyCircularQueue.prototype.deQueue = function() {
        
    delete this.arr[0]; //first one will always be dequeued

    this.arr = putEmptyElementsInLast(this.arr);
	    
    this.headCount +=1;
    this.tailCount -=1;
    
    return true;
};

function putEmptyElementsInLast (arr, numToRearrangeArray) {
    
    const arrTest = [...arr];

    for(i=0; i<arrTest.length; i++) {
        var p1 = arrTest[i];
        var p2 = arrTest[i+1];

        if(isNaN(p1) && !isNaN(p2)) {
            arrTest[i] = p2;
            delete arrTest[i+1]; //remove the next element value so we can move the contents
        }

//         console.log('p1: ', p1, '||| p2: ', p2);

        if (isNaN(p2) && (arrTest.length) === i) break;
    }

    return arrTest;
}


/**
 * @return {number}
 */
MyCircularQueue.prototype.Front = function() {
    return this.arr[0] ?? -1;
};

/**
 * @return {number}
 */
MyCircularQueue.prototype.Rear = function() {
    return this.arr[this.arr.length-1] ?? -1;    
};

/**
 * @return {boolean}
 */
MyCircularQueue.prototype.isEmpty = function() {
    return this.arr.filter(x => x || !isNaN(x)).length === 0;
};

/**
 * @return {boolean}
 */
MyCircularQueue.prototype.isFull = function() {
    return this.arr.filter(x => x || !isNaN(x)).length > 0;
};

/** 
 * Your MyCircularQueue object will be instantiated and called as such:
 * var obj = new MyCircularQueue(k)
 * var param_1 = obj.enQueue(value)
 * var param_2 = obj.deQueue()
 * var param_3 = obj.Front()
 * var param_4 = obj.Rear()
 * var param_5 = obj.isEmpty()
 * var param_6 = obj.isFull()
 */