Piral LitEl ·

This is a plugin that only has a peer dependency to lit-element. What piral-litel brings to the table is a set of Pilet API extensions that can be used with piral or piral-core.

The set includes a LitElement converter for any component registration, as well as a fromLitEl shortcut and a LitElExtension component.

By default, these API extensions are not integrated in piral, so you'd need to add them to your Piral instance.

Documentation

The following functions are brought to the Pilet API.

fromLitEl()

Transforms a standard LitElement component into a component that can be used in Piral, essentially wrapping it with a reference to the corresponding converter.

LitElExtension

The name of the extension slot component to be used in LitElement components. This is usually not needed, as it is made available via a custom element named litel-extension. For safety measure LitElExtension.name could be used to find the name of the custom element.

Usage

::: summary: For pilet authors

You can use the fromLitEl function from the Pilet API to convert your LitElement components to components usable by your Piral instance.

Example use:

import { PiletApi } from '<name-of-piral-instance>';
import './LitElPage';

export function setup(piral: PiletApi) {
  piral.registerPage('/sample', piral.fromLitel('my-page'));
}

Within LitElement components the Piral LitElement extension component can be used by referring to litel-extension, e.g.,

<litel-extension name="name-of-extension"></litel-extension>

Alternatively, if piral-litel has not been added to the Piral instance you can install and use the package also from a pilet directly.

import { PiletApi } from '<name-of-piral-instance>';
import { fromLitel } from 'piral-litel/convert';
import './LitElPage';

export function setup(piral: PiletApi) {
  piral.registerPage('/sample', fromLitel('my-page'));
}

:::

::: summary: For Piral instance developers

Using LitElement with Piral is as simple as installing piral-litel and lit-element@^2.

import { createLitElApi } from 'piral-litel';

The integration looks like:

const instance = createInstance({
  // important part
  plugins: [createLitElApi()],
  // ...
});

The lit-element and @webcomponents/webcomponentsjs packages should be shared with the pilets via the package.json:

{
  "importmap": {
    "imports": {
      "@webcomponents/webcomponentsjs": "",
      "lit-element": ""
    }
  }
}

:::

Preparing Pilets

Unfortunately, LitElement is quite sensitive regarding how its transpiled. Right now the only way to be sure that classes are indeed transpiled as they should (from perspective of LitElement) is to place the following snippet in the package.json of each pilet using piral-litel:

{
  // ...
  "browserslist": [
    "last 1 chrome versions"
  ],
  // ...
}

This will make sure that ES6 classes are used, which is required for web components to work properly.

License

Piral is released using the MIT license. For more information see the license file.