npm install hylian --save

_{^{Hylians are a race of humans from Zelda, of which Link is one. Hylian → Link → Doubly & Singly Linked Lists.}}
Quick and easy doubly and singly linked immutable list implementation that allows for inserting, removing and shifting.

example: heroku

     

Getting Started

⚠️ Before you begin with Hylian it's crucial to note that Hylian uses immutability, and therefore may not be what you're expected from a linked list. When you perform any action on your list, a new list will be returned, rather than mutating the existing.

However if immutability is perfect for you, then let's dive straight in. All lists are instantiated by using create function – which is both a named export and the default export.

import { create } from 'hylian';

const a = create([1, 2, 3, 4, 5]);
const b = a.next();
const c = b.previous();

console.log(a.data); // 1
console.log(b.data); // 2
console.log(c.data); // 3

At the heart of a linked list is the ability to traverse the list using the next and previous functions. By default Hylian is an infinite list, which means both functions will simply cycle the list over and over again. Overriding the default requires the passing of finite: true.

import { create } from 'hylian';

const a = create([1, 2, 3, 4, 5]);
const b = create([1, 2, 3, 4, 5], { finite: true });

console.log(a.previous().data); // 5
console.log(b.previous().data); // 5 (remains unchanged)

By default Hylian uses doubly-linked lists, however by passing the type you can use singly-linked lists instead, which only allow you to traverse forward.

import { create, listType } from 'hylian';

const a = create([1, 2, 3, 4, 5], { type: listType.single });

console.log(a.next().data); // 2
console.log(b.previous().data); // TypeError: `previous` is not a function.

Inserting Items

Linked lists allow the inserting of items both relative to the container, and relative to the list as a whole.

import { create } from 'hylian';

const a = create([1, 2, 3, 4, 5]);
const b = a.end();
const c = b.insert.after(6, 7, 8, 9, 10);
const d = b.next();

console.log(a.data); // 1
console.log(b.data); // 5 
console.log(c.data); // 5 (index does not change)
console.log(d.data); // 6

console.log(d.size()); // 10

You're also able to remove.before and remove.current. With remove.current the index won't change but the value represented by the index will change, because a new item now occupies the current index's space.

Using the clear you're able to remove all items from the list. Notably when the list is empty you won't be able to remove items — as there aren't any — nor will you be permitted to insert.before, insert.after as the context has disappeared, and you can therefore only operate on the list relative to the list as a whole.

Removing Items

Removing items in a linked list are performed in a similar fashion to inserting – you have access to insert.start, insert.before, insert.after and insert.end.

import { create } from 'hylian';

const a = create([1, 2, 3, 4, 5]);
const b = a.next().next();
const c = b.remove.after();
const d = c.next();

console.log(a.data); // 1
console.log(b.data); // 3
console.log(c.data); // 3 (index does not change)
console.log(d.data); // 5

console.log(d.size()); // 4