actualize

Actualize is a very efficient and fast DOM patching algorithm. It's inspired by morphdom and nanomorph. It works with a real DOM, so a virtual DOM is not required.

Installation

npm install actualize

Usage

ES2015

import actualize from 'actualize'

CommonJS

const actualize = require('actualize')

Browser

<script src="https://unpkg.com/actualize@latest/dist/actualize.js"></script>

It injects actualize global into your environment.

Example

import actualize from 'actualize'

const nodeA = document.createElement('button')
nodeA.textContent = 'Open'

const nodeB = document.createElement('button')
nodeB.className = 'pressed'
nodeB.textContent = 'Close'

nodeA.outerHTML === '<button>Open</button>' // true

actualize(nodeA, nodeB)

nodeA.outerHTML === '<button class="pressed">Close</button>' // true

DOM generation

Actualize can be used in combination with domb, a convenient tool for generating DOM trees. The above example can be rewriten using domb as follows:

import actualize from 'actualize'
import { button } from 'domb'

const nodeA = button({ children : 'Open '})
const nodeB = button({ children : 'Close', className : 'pressed' })

actualize(nodeA, nodeB)

Reordering lists

It's common to work with lists of items in the DOM. Adding, removing or reordering items in a list can be quite expensive. To optimize this, you can add an id attribute to the DOM node. When changing the order of nodes, actualize will compare nodes with the same ID with each other, which will lead to a much smaller numbers of re-renders. The getKey option can be used to configure the key property for this purpose (see below).

API

actualize(treeA, treeB, options)

The actualize function supports the following arguments:

• treeA: Node — node for updating
• treeB: Node — node to which treeA should be updated
• options: object — see below supported options

The return value will usually be treeA. However, in situations where treeA is incompatible with treeB (either a different node type or a different tag name) then treeB will be returned.

Supported options (all optional):

Option: type	Description
childrenOnly: boolean	Update only the child nodes of the treeA, the element itself will be skipped. The default value is false.
getKey: function(node)	Called to get a custom key of the node in a child list. The default value is node.id.
nodeWillMount: function(nodeB)	Called before a node from the B tree is mounted to the A tree.
nodeDidMount: function(nodeB)	Called after a node from the B tree has been mounted to the A tree.
nodeWillUnmount: function(nodeA)	Called before a node in the A tree is unmounted.
nodeDidUnmount: function(nodeA)	Called after a node in the A tree has been unmounted.
nodeWillUpdate: function(nodeA, nodeB)	Called before updating a node in the A tree.
nodeDidUpdate: function(nodeA, nodeB)	Called after updating a node in the A tree.
childrenWillUpdate: function(nodeA, nodeB)	Called before updating the child nodes of an element in the A tree.
childrenDidUpdate: function(nodeA, nodeB)	Called after updating the child nodes of an element in the A tree.

⚠️ actualize will modify the treeB and it should be discarded after use.

License

The MIT License (MIT)