html code send to prism-highlighter is parsed by polymer

[Stefdv]

Description

code send to prism-highlighter element is actually 'parsed' by polymer.
used prism-demo as example
https://github.com/PolymerElements/prism-element/blob/master/demo/prism-demo.html
<dom-module id="my-element">
<template>
console.log('hello world")
</template>
</dom-module>
<my-element></my-element>
<prism-demo code="<my-element></my-element>" lang="html"></prism-demo>

Expected outcome

hello world

Actual outcome

hello world
hello world

Browsers Affected

• Chrome
• Firefox
• [?] Safari 9
• [?] Safari 8
• [?] Safari 7
• Edge
• [?] IE 11
• [?] IE 10

[TimvdLippe]

This is also happening with bindings inside <script type="text/markdown">.

[masonlouchart]

In my case, when I wait a few seconds before passing my HTML to Prism it is not parsed by Polymer. I guess Prism is not ready the first time my element renders and the source code I want to be highlighted is passed.

Workaround: wait 50ms at least for the 1st render.

setTimeout(() => {
    parent.dispatchEvent(event);
    output.innerHTML = event.detail.code;
}, 50);