andrewrjones / doubly-linked-list-js

Javascipt implementation of a doubly linked list.

DoublyLinkedList

This is a Javascipt implementation of a doubly linked list.

I needed a doubly linked list for a project I was doing, and thought I would post the code here in case it was useful for anyone else.

Works in both the browser and node.js.

Synopsis

node.js.

var DLL = require('doubly-linked-list.js');
var list = new DLL.DoublyLinkedList();

list.append('data1');
node = list.append('data2');
list.append('data3');

size = list.size; // 3
node.prev.data; // data1
node.next.data; // data3

node = list.item(1);
data = node.data; // data2
prev = node.prev; // data1
next = node.next; // data3

node = list.head();
data = node.data; // data1

node = list.tail();
data = node.data; // data3

list.prepend('data4');

size = list.size; // 4

node = list.head();
data = node.data; // data4
prev = node.prev; // null
next = node.next; // data1

node.append('frog');
appended = node.next; // frog
next = appended.next; // data1

next.remove();
afterRemoved = appended.next; // data2

afterRemoved.prepend('bird');
prepended = appended.next; // bird

Browser.

<script src="doubly-linked-list.js"></script>
<script>
    var list = new DLL.DoublyLinkedList();
    // as above
</script>

API

new DoublyLinkedList()

Creates a new DoublyLinkedList. Takes no arguments.

append(data)

Appends a node to the end of the list. Returns the node.

See item(index) for notes on the structure of the node returned.

prepend(data)

Prepends a node to the end of the list. Returns the node.

See item(index) for notes on the structure of the node returned.

item(index)

Returns the node at the specified index. The index starts at 0.

Note: Nodes returned support various operations. See the section about node objects for a list of supported properties and methods.

head()

Returns the node at the head of the list. See item(index) for notes on the structure of the node returned.

tail()

Returns the node at the tail of the list. See item(index) for notes on the structure of the node returned.

size()

Returns the size of the list.

Node Objects

When a list/node operation returns a node, it is in fact an object with the following properties and methods:

prev

The node before the current one, or null if this node is the list head.

next

The node after the current one, or null if this node is the list tail.

data

The data stored in the node when it was created.

remove()

Removes the node from the list.

append(data)

Creates a new node with a data value of data and adds it to the list after the current node. Returns the new node.

prepend(data)

Creates a new node with a data value of data and adds it to the list before the current node. Returns the new node.

Build status

More

https://github.com/playcraft/gamecore.js/blob/master/src/linkedlist.js