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<prism-highlighter>
Syntax highlighting via Prism.
Place a <prism-highlighter> in your document, preferably as a direct child of <body>. It will listen for syntax-highlight events on its parent element, and annotate the code being provided via that event.
The syntax-highlight event's detail is expected to have a code property containing the source to highlight. The event detail can optionally contain a lang property, containing a string like "html", "js", etc.
This flow is supported by <marked-element>.
See: Documentation, Demo.
Usage
Installation
npm install --save @polymer/prism-element
In an html file
<html>
<body>
<div id="parent">
<prism-highlighter></prism-highlighter>
<div id="output"></div>
</div>
</body>
<script type="module">
import '@polymer/prism-element/prism-highlighter.js';
import '@polymer/prism-element/prism-theme-default.js';
import '@polymer/polymer/lib/elements/custom-style.js';
import {html} from '@polymer/polymer/lib/utils/html-tag.js';
// import prism theme styles
const template = html`
<custom-style>
<style include="prism-theme-default"></style>
</custom-style>
`;
document.head.appendChild(template.contents);
const parent = document.getElementById('parent');
const output = document.getElementById('output');
const ev = new CustomEvent('syntax-highlight');
// enter code and language here
ev.detail = {
code: 'p { background-color: blue }',
lang: 'css',
};
parent.dispatchEvent(ev);
// detail is modified by prism-highlighter
output.innerHTML = ev.detail.code;
</script>
</html>
In a Polymer 3 element
import {PolymerElement, html} from '@polymer/polymer';
import '@polymer/prism-element/prism-element.js';
import '@polymer/prism-element/prism-highlighter.js';
import '@polymer/prism-element/prism-theme-default.js';
class SampleElement extends PolymerElement {
static get template() {
return html`
<style include="prism-theme-default"></style>
<div id="parent">
<prism-highlighter></prism-highlighter>
<div id="output"></div>
</div>
`;
}
connectedCallback() {
super.connectedCallback();
const ev = new CustomEvent('syntax-highlight');
// enter code and language here
ev.detail = {
code: 'p { background-color: blue }',
lang: 'css',
};
this.$.parent.dispatchEvent(ev);
// detail is modified by prism-highlighter
this.$.output.innerHTML = ev.detail.code;
}
}
customElements.define('sample-element', SampleElement);
Contributing
If you want to send a PR to this element, here are the instructions for running the tests and demo locally:
Installation
git clone https://github.com/PolymerElements/prism-element
cd prism-element
npm install
npm install -g polymer-cli
Running the demo locally
polymer serve --npm
open http://127.0.0.1:<port>/demo/
Running the tests
polymer test --npm
