Systems >> Overlays >> Overview ||10
Supports different types of overlays like dialogs, toasts, tooltips, dropdown, etc.
Manages their position on the screen relative to other elements, including other overlays.
Its purpose is to make it easy to use our Overlay System declaratively. It can be easily extended where needed, to override event listeners and more.
See lion-dialog and lion-tooltip for example Web Component implementations using the Overlay System.
Features
- local rendering (at dom location)
- positioning with popper.js
- global rendering (at body level)
- fully accessible
- flexible to build multiple overlay components
- lion-overlay web component:
- Show content when clicking the invoker
- Have a
.config
object to set or update the OverlayController's configuration
- OverlaysManager, a global repository keeping track of all different types of overlays
- OverlayController, a single controller class for handling overlays
- OverlayMixin, a mixin that can be used to create webcomponents that use the OverlayController under the hood
Usually you will use lion-dialog
(or lion-tooltip
if this makes more sense).
Installation
npm i --save @lion/overlays
npm i --save @lion/dialog
Example
import '@lion/dialog/define';
html`
<lion-dialog .config=${{
placementMode: 'global',
viewportConfig: { placement: 'bottom-right' },
}}>
<div slot="content">
This is an overlay
<button
@click=${e => e.target.dispatchEvent(new Event('close-overlay', { bubbles: true }))}
>x</button>
<div>
<button slot="invoker">
Click me
</button>
</lion-dialog>
`;
Or by creating a controller yourself
import { OverlayController } from '@lion/overlays';
const ctrl = new OverlayController({
...withModalDialogConfig(),
invokerNode,
contentNode,
});
Or creating your own Web Component which uses the Overlay System
import { LitElement, html } from '@lion/core';
import { OverlayMixin, withModalDialogConfig } from '@lion/overlays';
class MyOverlayComponent extends OverlayMixin(LitElement) {
_defineOverlayConfig() {
return {
...withModalDialogConfig(),
};
}
_setupOpenCloseListeners() {
super._setupOpenCloseListeners();
this.__toggle = () => {
this.opened = !this.opened;
};
if (this._overlayInvokerNode) {
this._overlayInvokerNode.addEventListener('click', this.__toggle);
}
}
_teardownOpenCloseListeners() {
super._teardownOpenCloseListeners();
if (this._overlayInvokerNode) {
this._overlayInvokerNode.removeEventListener('click', this.__toggle);
}
}
render() {
return html`
<slot name="invoker"></slot>
<div id="overlay-content-node-wrapper">
<slot name="content"></slot>
</div>
`;
}
}
Rationales
Please check the system rationals folder, where we go more in-depth.
Aria roles
- No
aria-controls
as support for it is not quite there yet - No
aria-haspopup
. People knowing the haspopup and hear about it don’t expect a dialog to open (at this moment in time) but expect a sub-menu. Until support for the dialog value has better implementation, it’s probably best to not use aria-haspopup on the element that opens the modal dialog.