JavaScript/Data-Structures/Queue/Queue.js at master · flexycode/JavaScript · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
/* Queue
 * A Queue is a data structure that allows you to add an element to the end of
 * a list and remove the item at the front. A queue follows a FIFO (First In First Out)
 * system, where the first item to enter the queue is the first to be removed,
 * All these operation complexities are O(1).
 * This implementation following the linked list structure.
 */

classQueue{
 #size

constructor(){
this.head=null
this.tail=null
this.#size =0

returnObject.seal(this)
}

getlength(){
returnthis.#size
}

/**
 * @description - Add a value to the end of the queue
 * @param {*} data
 * @returns {number} - The current size of queue
 */
enqueue(data){
constnode={ data,next: null}

if(!this.head&&!this.tail){
this.head=node
this.tail=node
}else{
this.tail.next=node
this.tail=node
}

return++this.#size
}

/**
 * @description - Removes the value at the front of the queue
 * @returns {*} - The first data of the queue
 */
dequeue(){
if(this.isEmpty()){
thrownewError('Queue is Empty')
}

constfirstData=this.peekFirst()

this.head=this.head.next

if(!this.head){
this.tail=null
}

this.#size--

returnfirstData
}

/**
 * @description - Return the item at the front of the queue
 * @returns {*}
 */
peekFirst(){
if(this.isEmpty()){
thrownewError('Queue is Empty')
}

returnthis.head.data
}

/**
 * @description - Return the item at the tail of the queue
 * @returns {*}
 */
peekLast(){
if(this.isEmpty()){
thrownewError('Queue is Empty')
}

returnthis.tail.data
}

/**
 * @description - Return the array of Queue
 * @returns {Array<*>}
 */
toArray(){
constarray=[]
letnode=this.head

while(node){
array.push(node.data)
node=node.next
}

returnarray
}

/**
 * @description - Return is queue empty or not
 * @returns {boolean}
 */
isEmpty(){
returnthis.length===0
}
}

exportdefaultQueue