JarCasting
<demo-snippet>
demo-snippet is a helper element that displays the source of a code snippet and its rendered demo. It can be used for both native elements and Polymer elements.
See: Documentation, Demo.
Usage
Installation
npm install --save @polymer/iron-demo-helpers
In an html file
<html>
<head>
<script type="module">
import '@polymer/iron-demo-helpers/demo-snippet.js';
import '@polymer/paper-checkbox/paper-checkbox.js';
</script>
</head>
<body>
<demo-snippet>
<template>
<input type="date">
<paper-checkbox>Checkbox</paper-checkbox>
</template>
</demo-snippet>
</body>
</html>
In a Polymer 3 element
import {PolymerElement, html} from '@polymer/polymer';
import '@polymer/iron-demo-helpers/demo-snippet.js';
import '@polymer/paper-checkbox/paper-checkbox.js';
class SampleElement extends PolymerElement {
static get template() {
return html`
<demo-snippet>
<template>
<input type="date">
<paper-checkbox>Checkbox</paper-checkbox>
</template>
</demo-snippet>
`;
}
}
customElements.define('sample-element', SampleElement);
<url-bar>
url-bar is a helper element that displays a simple read-only URL bar if and only if the page is in an iframe. In this way we can demo elements that deal with the URL in our iframe-based demo environments.
If the page is not in an iframe, the url-bar element is not displayed.
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/iron-demo-helpers
cd iron-demo-helpers
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
Known Issues
If you add a script type="module" inside a demo-snippet, the demo will not be functional on non-module browsers (like IE11). If you need to use a script type="module" and want to display its code in the demo-snippet, a possible workaround is to duplicate the contents of the script outside of the demo-snippet -- that way polymer serve (or whatever solution you're using to ES5-ify the code) will convert the main document module to UMD, but will leave the displayed code untouched. Here is an example:
<body>
<demo-snippet>
<template>
...
<script type="module">
import {SomeExport} from '../foo.js';
SomeExport.aFunction();
</script>
</template>
</demo-snippet>
<!-- Hack: on non-module browsers the demo-snippet script doesn't
do anything, so add the content here again to make sure the demo works -->
<script type="module">
import {SomeExport} from '../foo.js';
SomeExport.aFunction();
</script>
</body>
