Dialog

Basic modal overlay that the user typically dismisses with an explicit action

Here's a dialog.

This paragraph has a z-index, but should appear behind the dialog. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse sed lorem scelerisque, blandit libero vitae, dapibus nisl. Sed turpis diam, placerat a feugiat sed, maximus at velit. Ut sit amet semper sapien. Donec vitae leo ex. Duis eget quam sed metus tempor lobortis eget feugiat elit. Cras varius, arcu ac commodo tincidunt, lectus dui convallis nunc, quis maximus nisl erat ac mi. Phasellus et velit diam.

Demo: Clicking the button opens a simple dialog

Overview

Dialog is a basic type of Overlay that presents its assigned children as a basic modal dialog which appears on top of the main page content. The user must interact with the dialog before they can return to the page.

Dialog uses ModalBackdrop to add a backdrop behind the main overlay content.

Usage

import Dialog from 'elix/src/Dialog.js';
const dialog = new Dialog(); // or
const dialog = document.createElement('elix-dialog');

In HTML:

<script type="module" src="node_modules/elix/src/Dialog.js"></script>
<elix-dialog>
  <!-- Dialog contents go here -->
</elix-dialog>

As with other elements that use DialogModalityMixin, use modal overlays only when it's critical that you gain the user's attention, or when you need them to provide a response in order to continue. For all other overlay situations, consider using a Popup or other component using PopupModalityMixin.

For a simple form of Dialog that can be easily created in JavaScript to ask a single question, see AlertDialog.

Keyboard support

Dialog uses FocusCaptureMixin to wrap the keyboard focus within the dialog. The keyboard focus is initially on the dialog itself. Pressing Tab will cycle through the dialog's focusable elements. When the user reaches the last of the dialog's focusable elements, pressing Tab focuses the dialog again, repeating the cycle.

Pressing the Esc key closes the dialog.

See also

API

Ancestry: Dialog → OverlayReactiveElement → HTMLElement

Built with mixins AttributeMarshallingMixin, DialogModalityMixin, KeyboardMixin, OpenCloseMixin, OverlayMixin, ReactiveMixin, ShadowTemplateMixin, and SlotContentMixin.

By default, this uses these elements in the following roles:

Extended by classes AlertDialog and Drawer.

$ property

A convenient shortcut for looking up an element by ID in the component's Shadow DOM subtree.

Example: if component's template contains a shadow element <button id="foo">, you can use the reference this.$.foo to obtain the corresponding button in the component instance's shadow tree. The $ function is simply a shorthand for getElementById, so this.$.foo is the same as this.shadowRoot.getElementById('foo').

Type: object

Defined by ShadowTemplateMixin

backdropRole property

The class, tag, or template used for the optional backdrop element behind the overlay.

This can help focus the user's attention on the overlay content. Additionally, a backdrop can be used to absorb clicks on background page elements. For example, Dialog uses ModalBackdrop as an overlay backdrop in such a way.

Type: (component class constructor)|HTMLTemplateElement|string

Default: Backdrop

Defined by Overlay

close(closeResult) method

Close the component (if not already closed).

Some components like AlertDialog want to indicate why or how they were closed. To support such scenarios, you can supply a value to the optional closeResult parameter. This closeResult will be made available in the whenClosed promise and the state.closeResult member.

Parameters:

  • closeResult: objectan indication of how or why the element closed

Defined by OpenCloseMixin

closed property

True if the element is currently closed.

Type: boolean

Defined by OpenCloseMixin

closed event

Raised when the component closes.

Defined by OpenCloseMixin

closeFinished property

True if the element has completely closed.

For components not using asynchronous open/close effects, this property returns the same value as the closed property. For elements that have a true value of state.openCloseEffects (e.g., elements using TransitionEffectMixin), this property returns true only if state.effect is "close" and state.effectPhase is "after".

Type: boolean

Defined by OpenCloseMixin

defaultState property

The default state for the component. This can be extended by mixins and classes to provide additional default state.

Type: State

Defined by ReactiveMixin

frameRole property

The class, tag, or template used to contain the primary overlay content.

The frame element can be used to provide a border around the overlay content, and to provide visual effects such as a drop-shadow to help distinguish overlay content from background page elements.

Type: (component class constructor)|HTMLTemplateElement|string

Default: OverlayFrame

Defined by Overlay

open() method

Open the element (if not already opened).

Defined by OpenCloseMixin

opened property

True if the element is currently opened.

Type: boolean

Defined by OpenCloseMixin

opened event

Raised when the component opens.

Defined by OpenCloseMixin

opened-changed event

Raised when the opened/closed state of the component changes.

Defined by OpenCloseMixin

render() method

Render pending component changes to the DOM.

This method does nothing if the state has not changed since the last render call.

This method invokes all internal render methods. It then invoked componentDidMount (for first render) or componentDidUpdate (for subsequent renders).

Defined by ReactiveMixin

setState(changes) method

Update the component's state by merging the specified changes on top of the existing state. If the component is connected to the document, and the new state has changed, this returns a promise to asynchronously render the component. Otherwise, this returns a resolved promise.

Parameters:

  • changes: objectthe changes to apply to the element's state

Returns: Promise - resolves when the new state has been rendered

Defined by ReactiveMixin

state property

The component's current state. The returned state object is immutable. To update it, invoke setState.

Type: State

Defined by ReactiveMixin

[symbols.contentSlot] property

Defined by SlotContentMixin

[symbols.keydown]() method

See the symbols documentation for details.

Defined by KeyboardMixin

[symbols.render](changed) method

Internal method for rendering any recent changes in state to the DOM.

The default implementation of this method does nothing. Override this method in your component to update your component's host element and any shadow elements to reflect the component's new state. See the rendering example.

Be sure to call super in your method implementation so that your component's base classes and mixins have a chance to perform their own render work.

Parameters:

  • changed: objectdictionary of flags indicating which state members have changed since the last render

Defined by ReactiveMixin

toggle(opened) method

Toggle the open/close state of the element.

Parameters:

  • opened: booleantrue if the element should be opened, false if closed.

Defined by OpenCloseMixin

whenClosed() method

This method can be used as an alternative to listening to the "opened-changed" event, particularly in situations where you want to only handle the next time the component is closed.

Returns: Promise A promise that resolves when the element has completely closed, including the completion of any asynchronous opening effect.

Defined by OpenCloseMixin