1+ function LinkedList ( ) {
2+
3+ var Node = function ( element ) {
4+
5+ this . element = element ;
6+ this . next = null ;
7+ } ;
8+
9+ var length = 0 ;
10+ var head = null ;
11+
12+ this . append = function ( element ) {
13+
14+ var node = new Node ( element ) ,
15+ current ;
16+
17+ if ( head === null ) { //first node on list
18+ head = node ;
19+ } else {
20+
21+ current = head ;
22+
23+ //loop the list until find last item
24+ while ( current . next ) {
25+ current = current . next ;
26+ }
27+
28+ //get last item and assign next to added item to make the link
29+ current . next = node ;
30+ }
31+
32+ length ++ ; //update size of list
33+ } ;
34+
35+ this . insert = function ( position , element ) {
36+
37+ //check for out-of-bounds values
38+ if ( position >= 0 && position <= length ) {
39+
40+ var node = new Node ( element ) ,
41+ current = head ,
42+ previous ,
43+ index = 0 ;
44+
45+ if ( position === 0 ) { //add on first position
46+
47+ node . next = current ;
48+ head = node ;
49+
50+ } else {
51+ while ( index ++ < position ) {
52+ previous = current ;
53+ current = current . next ;
54+ }
55+ node . next = current ;
56+ previous . next = node ;
57+ }
58+
59+ length ++ ; //update size of list
60+
61+ return true ;
62+
63+ } else {
64+ return false ;
65+ }
66+ } ;
67+
68+ this . removeAt = function ( position ) {
69+
70+ //check for out-of-bounds values
71+ if ( position > - 1 && position < length ) {
72+
73+ var current = head ,
74+ previous ,
75+ index = 0 ;
76+
77+ //removing first item
78+ if ( position === 0 ) {
79+ head = current . next ;
80+ } else {
81+
82+ while ( index ++ < position ) {
83+
84+ previous = current ;
85+ current = current . next ;
86+ }
87+
88+ //link previous with current's next - skip it to remove
89+ previous . next = current . next ;
90+ }
91+
92+ length -- ;
93+
94+ return current . element ;
95+
96+ } else {
97+ return null ;
98+ }
99+ } ;
100+
101+ this . remove = function ( element ) {
102+
103+ var index = this . indexOf ( element ) ;
104+ return this . removeAt ( index ) ;
105+ } ;
106+
107+ this . indexOf = function ( element ) {
108+
109+ var current = head ,
110+ index = - 1 ;
111+
112+ //check first item
113+ if ( element == current . element ) {
114+ return 0 ;
115+ }
116+
117+ index ++ ;
118+
119+ //check in the middle of the list
120+ while ( current . next ) {
121+
122+ if ( element == current . element ) {
123+ return index ;
124+ }
125+
126+ current = current . next ;
127+ index ++ ;
128+ }
129+
130+ //check last item
131+ if ( element == current . element ) {
132+ return index ;
133+ }
134+
135+ return - 1 ;
136+ } ;
137+
138+ this . isEmpty = function ( ) {
139+ return length === 0 ;
140+ } ;
141+
142+ this . size = function ( ) {
143+ return length ;
144+ } ;
145+
146+ this . getHead = function ( ) {
147+ return head ;
148+ } ;
149+
150+ this . toString = function ( ) {
151+
152+ var current = head ,
153+ s = current . element ;
154+
155+ while ( current . next ) {
156+ current = current . next ;
157+ s += ', ' + current . element ;
158+ }
159+
160+ return s ;
161+ } ;
162+
163+ this . print = function ( ) {
164+ console . log ( this . toString ( ) ) ;
165+ }
166+ }
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