solution.js

/**
 * Initialize your data structure here. Set the size of the deque to be k.
 * @param {number} k
 */
var MyCircularDeque = function(k) {
    this.maxLength = k
    this.array = []
};

/**
 * Adds an item at the front of Deque. Return true if the operation is successful. 
 * @param {number} value
 * @return {boolean}
 */
MyCircularDeque.prototype.insertFront = function(value) {
    if (this.isFull()) return false
    
    this.array.unshift(value)
    return true
};

/**
 * Adds an item at the rear of Deque. Return true if the operation is successful. 
 * @param {number} value
 * @return {boolean}
 */
MyCircularDeque.prototype.insertLast = function(value) {
    if (this.isFull()) return false
    
    this.array.push(value)
    return true
};

/**
 * Deletes an item from the front of Deque. Return true if the operation is successful.
 * @return {boolean}
 */
MyCircularDeque.prototype.deleteFront = function() {
    if (this.isEmpty()) return false
    
    this.array.shift()
    return true
};

/**
 * Deletes an item from the rear of Deque. Return true if the operation is successful.
 * @return {boolean}
 */
MyCircularDeque.prototype.deleteLast = function() {
    if (this.isEmpty()) return false
    
    this.array.pop()
    return true
};

/**
 * Get the front item from the deque.
 * @return {number}
 */
MyCircularDeque.prototype.getFront = function() {
    if (this.isEmpty()) return -1
    return this.array[0]
};

/**
 * Get the last item from the deque.
 * @return {number}
 */
MyCircularDeque.prototype.getRear = function() {
    if (this.isEmpty()) return -1
    return this.array[this.array.length - 1]
};

/**
 * Checks whether the circular deque is empty or not.
 * @return {boolean}
 */
MyCircularDeque.prototype.isEmpty = function() {
    return this.array.length === 0
};

/**
 * Checks whether the circular deque is full or not.
 * @return {boolean}
 */
MyCircularDeque.prototype.isFull = function() {
    return this.array.length === this.maxLength
};

/** 
 * Your MyCircularDeque object will be instantiated and called as such:
 * var obj = Object.create(MyCircularDeque).createNew(k)
 * var param_1 = obj.insertFront(value)
 * var param_2 = obj.insertLast(value)
 * var param_3 = obj.deleteFront()
 * var param_4 = obj.deleteLast()
 * var param_5 = obj.getFront()
 * var param_6 = obj.getRear()
 * var param_7 = obj.isEmpty()
 * var param_8 = obj.isFull()
 */