@georapbox/mutation-observer-element
TypeScript icon, indicating that this package has built-in type declarations

2.0.1 • Public • Published

npm version npm license

<mutation-observer>

A custom element that offers a declarative interface to the MutationObserver API.

API documentationDemo

Install

$ npm install --save @georapbox/mutation-observer-element

Usage

Script

import { MutationObserverElement } from './node_modules/@georapbox/mutation-observer-element/dist/mutation-observer.js';

// Manually define the element.
MutationObserverElement.defineCustomElement();

Alternatively, you can import the automatically defined custom element.

import './node_modules/@georapbox/mutation-observer-element/dist/mutation-observer-defined.js';

Markup

<mutation-observer 
  attr="*"
  attr-old-value
  char-data
  char-data-old-value
  child-list
>
  <button class="btn-primary">Click to mutate me</button>
</mutation-observer>

API

Properties

Name Reflects Type Default Description
attr String "" A space-separated string of attribute names to monitor (e.g., "title class href"). Use "*" to monitor all attributes.
attrOldValue
attr-old-value
Boolean false Set to true to record the previous value of any attribute that changes when monitoring the node or nodes for attribute changes.
childList
child-list
Boolean false Set to true to monitor the target node for the addition of new child nodes or removal of existing child nodes.
charData
char-data
Boolean false Set to true to monitor the specified target node for changes to the character data contained within the node or nodes.
charDataOldValue
char-data-old-value
Boolean false Set to true to record the previous value of a node's text whenever the text changes on nodes being monitored.
disabled Boolean false Set to true to stop monitoring for mutations.

NOTE: From the properties above, at least one of attr, child-list or char-data must be present, otherwise, no changes are monitored and no mutation events are emitted.

Slots

Name Description
(default) The default slot where the target node or nodes to be monitored are placed.

Methods

Name Type Description Arguments
defineCustomElement Static Defines/registers the custom element with the name provided. If no name is provided, the default name is used. The method checks if the element is already defined, hence will skip trying to redefine it. elementName='mutation-observer'

Events

Name Description Event Detail
mutation-observer:mutate Emitted when the element is mutated. { mutationList: MutationRecord[]

Changelog

For API updates and breaking changes, check the CHANGELOG.

Development setup

Prerequisites

The project requires Node.js and npm to be installed on your environment. Preferrably, use nvm Node Version Manager and use the version of Node.js specified in the .nvmrc file by running nvm use.

Install dependencies

Install the project dependencies by running the following command.

npm install

Build for development

Watch for changes and start a development server by running the following command.

npm start

Linting

Lint the code by running the following command.

npm run lint

Testing

Run the tests by running any of the following commands.

npm test
npm run test:watch # watch mode

Build for production

Create a production build by running the following command.

npm run build

License

The MIT License (MIT)

Package Sidebar

Install

npm i @georapbox/mutation-observer-element

Weekly Downloads

1

Version

2.0.1

License

MIT

Unpacked Size

53.8 kB

Total Files

13

Last publish

Collaborators

  • georapbox