Progressive Web Components.


A list of tools and how-to that will improve your experience with DNA.

Syntax highlighting for templates

If you are using the html helper to generate template, you can install the lit-html VSCode extension to enable HTML syntax highlightinh.

Web Components Analyzer

WCA is a CLI that analyzes Web components and generates a report in many formats like JSON and Markdown in order to provide component documentation. It natively supports JSDoc comments and TypeScript syntax so a lot of informations are infered from the source code. WCA supports a large variety of frameworks and a DNA specific flavor is something we are considering. By the way, you can use JSDoc comments and some native features to properly get a report:


import { Component, customElements } from '@chialab/dna';

 * A map component based on mapbox-gl.
 * @fires zoom - The map zoom level changed.
 * @fires move - The map center point changed.
export class MapboxMap extends Component {
    static get observedAttributes() {
        return ['latitude', 'longitude'];

     * The latitude value for the map center.
    latitude: number;

     * The longitude value for the map center.
    longitude: number;

customElements.define('x-map', MapboxMap);


$ wca analyze src/dna-map.ts
# dna-map

A map component based on mapbox-gl.

## Properties

| Property    | Attribute   | Type     | Description                             |
| `latitude`  | `latitude`  | `number` | The latitude value for the map center.  |
| `longitude` | `longitude` | `number` | The longitude value for the map center. |

## Events

| Event  | Description                   |
| `move` | The map center point changed. |
| `zoom` | The map zoom level changed.   |

Storybook is a fantastic tool for components development: you can create samples for your elements, provide a documentation and an API reference, run accessibility tests and more. Since version 5.6, it also supports Web Components.

A DNA preset for storybook is available with full docs addon support and automatic Web Components Analyzer runs across your components for documentation and knobs. You can install it using the @chialab/storybook-dna package from NPM:

$ npm i @chialab/storybook-dna -D

Please follow the instructions in the preset README for the full configuration.

Typescript JSX IntrinsicElements

TypeScript supports JSX syntax, and it is able to provide typechecking and hints for component properties automatically if you use class constructors as tag name:

import { render } from '@chialab/dna';
import { Card } from './x-card';

render(<Card firstName="Alan" age={24} />, document.body);

But how does it work with defined custom elements? It is possibile to declare IntrinsicElements in order to bind element's tag name with its prototype:

import { Component, customElements } from '@chialab/dna';

class Card extends Component {

customElements.define('x-card', Card);

declare namespace JSX {
    interface IntrinsicElements {
        'x-card': Card;