Implementation of MutationObserver / DOM Mutation Observers as an Ember component.
npm install ember-cli-dom-observerImplementation of MutationObserver / DOM Mutation Observers as an Ember component.
Detailed Documentation
Uses
----
* Browser extensions - You've created a browser extension in Ember and
need to monitor changes to the DOM to trigger your extension.
* Overcome HTML shortcomings by allowing you to monitor changes to attributes, elements
and nodes (anything in the DOM).
* Hook into 3rd party components that you are otherwise unable to see changes that these components make to the
DOM (e.g. Jquery Addon).
* Troubleshooting - Examine misbehaving components as they change within the DOM.
Features
--------
* Fast DOM change event capture.
* Capture snapshot DOM change comparison events for specific elements.
* Any DOM change can be captured including very complex events.
* Finite control allowing you to select what elements are observed and what changes to monitor.
How does this work?
-------------------
By using the Ember component methodology to _wrap_ a
MutationObserver around
an HTML element (see example code below).
Further information on MutationObserver can be found in these excellent blog posts:
- Overview
- In-depth
- Screencast
* ember install ember-cli-dom-observer
``handlebars`
{{#mutation-observer
handleMutations=(action "handleMutations")
attributes=true
childList=true
characterData=true
subtree=true
attributeFilter='["JSON","string","array"]'
}}
{{/mutation-observer}}
`javascript
import Ember from 'ember';
export default Ember.Component.extend({
actions:
{
/**
* MutationObserver triggered events action handler
*
* @param {MutationRecord[]} mutationRecords The triggered mutation records
* @param {MutationObserver} observer
*/
handleMutations(mutationRecords, observer) {
// Do something with mutation records
}
}
})
`
In the example above MutationRecords
will be sent to the handleMutations() action function
when any changes (e.g. new
node was added) to the ordered list occur.This Addon can also be used as a standalone component by using the targetId property
to indicate the element to be observed as in the example below.
`handlebars
{{mutation-observer
handleMutations=(action "handleMutations")
attributes=false
childList=false
characterData=true
subtree=true
targetId="btn"}}
Button Text: {{buttonText}}
`javascript
import Ember from 'ember';
export default Ember.Component.extend(
{
buttonText: null, actions:
{
handleMutations(mutations, observer) {
let self=this;
mutations.forEach(function (mutation)
{
if (mutation.type === 'characterData') {
self.set('buttonText', mutation.target.textContent);
observer.takeRecords(); // Empty the mutation queue.
}
});
}
}
})
`IMPORTANT NOTE: It is possible to have more than one observed element (multiple mutation-observer components) on a
page and have each observed element use the same
action.
However this is not best practice,
and can cause recursion issues.Each element you wrap in a component or set as the targetId should have an individual
mutationHandler action.
See the code in tests/dummy/app/components/example-mutation.js for an examples of best practice and bad practice.Installation
*
git clone https://github.com/RyanNerd/ember-cli-dom-observer.git
* npm install or yarn installRunning Examples
*