css-observe

Fire a custom event whenever an element matching a specified selector is added.

Syntax

Example

<script type="module" src="../css-observe.js"></script>
<css-observe id="myObserver" observe selector="div[test]"></css-observe>
<div test>
    I am here
</div>

css-observe will fire event: latest-match-changed, and the newly added element can be obtained from event.detail.value.

It will only observe the selector within the same Shadow DOM realm where the element is placed. If the element is placed outside any ShadowDOM, it will observe the selector only outside any ShadowDOM. How cool is that?

Implementation

Based off of an idea found here

Viewing Your Element

$ polymer serve

Running Tests

$ npm tests