Javascript Data Structure Tutorial - Javascript Doubly Linked Lists

• « Previous
• Next »

With Doubly Linked Lists we can iterate list items back and forth.

Node class

function Node(element) { 
    this.element = element; 
    this.next = null; 
    this.previous = null; 
} 

Doubly Linked Lists

function Node(element) { 
    this.element = element; 
    this.next = null; 
    this.previous = null; 
} 

function LinkedList() { 
    this.head = new Node("head"); 
    this.find = find; 
    this.insert = insert; 
    this.display = display; 
    this.remove = remove; 
    this.findLast = findLast; 
    this.dispReverse = dispReverse; 
} 
function dispReverse() { 
    var currNode = this.head; 
    currNode = this.findLast(); 
    while (!(currNode.previous == null)) { 
        console.log(currNode.element); 
        currNode = currNode.previous; 
    } 
} 
function findLast() { 
    var currNode = this.head; 
    while (!(currNode.next == null)) { 
        currNode = currNode.next; 
    } 
    return currNode; 
} 
function remove(item) { 
    var currNode = this.find(item); 
    if (!(currNode.next == null)) { 
        currNode.previous.next = currNode.next; 
        currNode.next.previous = currNode.previous; 
        currNode.next = null; 
        currNode.previous = null; 
    } 
} 
function display() { 
    var currNode = this.head; 
    while (!(currNode.next == null)) { 
        console.log(currNode.next.element); 
        currNode = currNode.next; 
    } 
} 
function find(item) { 
    var currNode = this.head; 
    while (currNode.element != item) { 
        currNode = currNode.next; 
    } 
    return currNode; 
} 
function insert(newElement, item) { 
    var newNode = new Node(newElement); 
    var current = this.find(item); 
    newNode.next = current.next; 
    newNode.previous = current; 
    current.next = newNode; 
} 
var cities = new LinkedList(); 
cities.insert("C", "head"); 
cities.insert("R", "C"); 
cities.insert("C", "R"); 
cities.insert("A", "C"); 
cities.display(); 
cities.remove("C"); 
cities.display(); 
cities.dispReverse(); 

The code above generates the following result.

• Next »
• « Previous