LinkedList.js

A simple doubly linked list implementation in Javascript.

Installation

npm install linkedlist-js

Usage

require the module...

var List = require('linkedlist-js').List;

instantiate a List object...

var list = new List();
 
// PUSH!
list.push('HUEHUE');

Traversing the List

with each(callback)

list.each(function (index, node) {
    console.log(index + ': ' + node.value());
});

like a badass

var node = list.head();
 
while (node != null) {
    console.log(node.value());
    node = node.next();
}

List API

Adding Nodes

push(value)

Creates a node with the value specified, adds it to the end of the list and returns the Node object.

var a = list.push('A');
a.value(); //'A'

unshift(value)

Creates a node with the value specified, adds it to the beginning of the list and returns the Node object.

var b = list.unshift('B');
b.value(); //'B'

Accessing Nodes

pop

Returns the tail Node and removes it from the list.

var list = new List();
list.push('A');
list.push('B');

list.pop().value(); //'B'

shift

Returns the head Node and removes it from the list.

var list = new List();
list.push('A');
list.push('B');

list.shift().value(); //'A'

get(index)

Returns the Node at the specified index. (Linear Lookup, not very performant)

var list = new List();
list.push('A');
list.push('B');
list.push('C');
 
list.get(1).value(); //'B'

Peeking

head()

Returns the head Node or null in list is empty

var list = new List();
var node_a = list.push('A');
var node_b = list.push('B');
 
list.head() === node_a; // true

tail()

Returns the tail Node or null in list is empty

var list = new List();
var node_a = list.push('A');
var node_b = list.push('B');
 
list.tail() === node_b; // true

Searching

find(value)

Find the node with the specified value and returns it. (Linear search, not very performant)

var list = new List();
list.push('A');
var node_b = list.push('B');
 
list.find('B') === node_b; // true

Misc

set(index, value)

Sets the value of the Node at the specifiec index.

var list = new List();
list.push('A');
 
list.set(0, 'B');
list.head().value(); // 'B'

count()

Returns the number of Nodes in the list.

var list = new List();
list.push('A');
list.push('B');
 
list.count(); // 2

isEmpty()

Returns true if list has no Nodes and false if otherwise.

var list = new List();
list.isEmpty(); // true
 
list.push('A');
list.isEmpty(); // false

truncateTo(length)

Truncates the list to the specified size.

var list = new List();
list.push('A');
list.push('B');

list.truncateTo(1);
list.count(); // 1

empty()

Same as calling truncateTo(0). Empties the list.

var list = new List();
list.push('A');
list.push('B');

list.empty();

list.count();   // 0
list.isEmpty(); // true

asArray()

Returns the list as an Array.

var list = new List();
list.push('A');
list.push('B');
 
list.asArray(); // ['A', 'B']

Node API

Getters

value()

Returns the value of the Node

previous()

Returns the previous Node in the list of null if the node is the forst Node.

next()

Returns the next Node in the list of null if the node is the last Node.

Setters

set(value)

Sets the value of the node

var node = new Node();
node.set('A');

node.value(); // 'A'

setPrevious(Node node)

Sets the previous pointer of the Node

var node_a = new Node();
var node_b = new Node();
node_b.setPrevious(node_a);

node_b.previous() === node_a; // true

setNext(Node node)

Sets the next pointer of the Node

var node_a = new Node();
var node_b = new Node();
node_a.setNext(node_b);

node_a.next() === node_b; // true

Misc

isHead()

Retunrs true if the node is the first node in the list.

var list = new List();
list.push('A');
list.push('B');
 
list.head().isHead(); // true

isTail()

Retunrs true if the node is the last node in the list.

var list = new List();
list.push('A');
list.push('B');
 
list.tail().isTail(); // true

Running Tests

npm test

if you have mocha installed, you may also run

mocha tests