PlainOptionList

Given a string value for a named boolean attribute, return true if the value is either: a) the empty string, or b) a case-insensitive match for the name.

This is native HTML behavior; see the MDN documentation on boolean attributes for the reasoning.

Given a null value, this return false. Given a boolean value, this return the value as is.

Parameters:

• name: string –
• value: string|boolean|null –

Defined by AttributeMarshallingMixin

Look for an item which is available in the given state..

The options parameter can accept options for:

• direction: 1 to move forward, -1 to move backward
• index: the index to start at, defaults to state.currentIndex
• wrap: whether to wrap around the ends of the items array, defaults to state.cursorOperationsWrap.

If an available item was found, this returns its index. If no item was found, this returns -1.

Parameters:

• state: PlainObject –
• options: PlainObject –

Returns: number

Defined by ItemsCursorMixin

See contentSlot.

Defined by SlotContentMixin

The index of the current item, or -1 if no item is current.

Type: number

Defined by CursorAPIMixin

Raised when the currentIndex property changes.

Defined by CursorAPIMixin

The current item, or null if no item is current.

Type: Element

Defined by CursorAPIMixin

True if the list should always have a current item (if it has items).

Type: boolean

Default: false

Defined by CursorAPIMixin

True if cursor operations wrap from last to first, and vice versa.

Type: boolean

Default: false

Defined by CursorAPIMixin

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

Type: PlainObject

Defined by ReactiveMixin

Flash the current item.

By default, this uses a heuristic to guess whether the menu was closed by a keyboard or mouse (on desktop). If so, the menu flashes the current item off then back on, emulating the menu item selection effect in macOS. Otherwise, it does nothing.

Defined by OptionList

The ID of the form element with which this element is associated, or null if the element is not associated with any form. This is provided for consistency with the native HTML form property.

Type: string

Defined by FormElementMixin

Extract the text from the given item.

The default implementation returns an item's aria-label, alt attribute, innerText, or textContent, in that order. You can override this to return the text that should be used.

Parameters:

• item: Element –

Returns: string

Defined by ItemsTextMixin

Interprets goDown to mean "move to the next item".

Defined by DirectionCursorMixin

Interprets goEnd to mean "move to the last item".

Defined by DirectionCursorMixin

Moves to the first item in the list.

Returns: Boolean True if the current item changed, false if not.

Defined by CursorAPIMixin

Move to the last item in the list.

Returns: Boolean True if the current item changed

Defined by CursorAPIMixin

Interprets goLeft to mean "move to the previous item".

If the element has a rightToLeft property and it is true, then this moves to the next item.

Defined by DirectionCursorMixin

Move to the next item in the list.

If the list has no current item, the first item will become current.

Returns: Boolean True if the current item changed

Defined by CursorAPIMixin

Moves to the previous item in the list.

If the list has no current item, the last item will become current.

Returns: Boolean True if the current item changed

Defined by CursorAPIMixin

Interprets goRight to mean "move to the next item".

If the element has a rightToLeft property and it is true, then this moves to the previous item.

Defined by DirectionCursorMixin

Interprets goStart to mean "move to the first item".

Defined by DirectionCursorMixin

Go to the first item whose text content begins with the given prefix.

Parameters:

• prefix: string – The prefix string to search for

Returns: boolean

Defined by KeyboardPrefixCursorMixin

Interprets goUp to mean "move to the previous item".

Defined by DirectionCursorMixin

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[ids].foo to obtain the corresponding button in the component instance's shadow tree. The ids property is simply a shorthand for getElementById, so this[ids].foo is the same as this[shadowRoot].getElementById('foo').

Type: object

Defined by ShadowTemplateMixin

Move to the first item in the set.

Returns: Boolean True if the current item changed, false if not.

Defined by ItemsCursorMixin

Move to the last item in the set.

Returns: Boolean True if the current item changed, false if not.

Defined by ItemsCursorMixin

Move to the next item in the set.

If no item is current, move to the first item.

Returns: Boolean True if the current item changed, false if not.

Defined by ItemsCursorMixin

Move to the previous item in the set.

If no item is current, move to the last item.

Returns: Boolean True if the current item changed, false if not.

Defined by ItemsCursorMixin

The current set of items drawn from the element's current state.

Type: Array.

Defined by ItemsAPIMixin

Raised when the items property changes.

Defined by ItemsAPIMixin

See the symbols documentation for details.

Defined by KeyboardMixin

The name of the form field that will be filled with this element's value. This is an analogue of the standard HTML name property.

Type: string

Defined by FormElementMixin

Scroll down one page.

Defined by KeyboardPagedCursorMixin

Scroll up one page.

Defined by KeyboardPagedCursorMixin

Render the indicated 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: ChangedFlags – dictionary of flags indicating which state members have changed since the last render

Defined by ReactiveMixin

Render any pending component changes to the DOM.

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

ReactiveMixin will invoke this method following a setState call; you should not need to invoke this method yourself.

This method invokes the internal render method, then invokes the rendered method.

Defined by ReactiveMixin

Perform any work that must happen after state changes have been rendered to the DOM.

The default implementation of this method does nothing. Override this method in your component to perform work that requires the component to be fully rendered, such as setting focus on a shadow element or inspecting the computed style of an element. If such work should result in a change in component state, you can safely call setState during the rendered method.

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 post-render work.

Parameters:

• changed: ChangedFlags –

Defined by ReactiveMixin

Scroll the current item completely into view, minimizing the degree of scrolling performed.

Blink has a scrollIntoViewIfNeeded() function that does something similar, but unfortunately it's non-standard, and in any event often ends up scrolling more than is absolutely necessary.

This scrolls the containing element defined by the scrollTarget property. By default, it will scroll the element itself.

Defined by CursorInViewMixin

The element that should be scrolled to get the selected item into view.

By default, this uses the defaultScrollTarget helper to find the most likely candidate for scrolling. You can override this property to directly identify which element should be scrolled.

See also scrollTarget.

Defined by CursorInViewMixin

The index of the selected item, or -1 if no item is selected.

Type: number

Defined by SingleSelectAPIMixin

Raised when the selectedIndex property changes.

Defined by SingleSelectAPIMixin

The selected item, or null if no item is selected.

Type: Element

Defined by SingleSelectAPIMixin

The text content of the selected item.

Setting this value to a string will attempt to select the first list item whose text matches that string. Setting this to a string not matching any list item will result in no selection.

Type: string

Defined by SelectedTextAPIMixin

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: PlainObject – the changes to apply to the element's state

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

Defined by ReactiveMixin

The component's current state.

The returned state object is immutable. To update it, invoke internal.setState.

It's extremely useful to be able to inspect component state while debugging. If you append ?elixdebug=true to a page's URL, then ReactiveMixin will conditionally expose a public state property that returns the component's state. You can then access the state in your browser's debug console.

Type: PlainObject

Defined by ReactiveMixin

Ask the component whether a state with a set of recently-changed fields implies that additional second-order changes should be applied to that state to make it consistent.

This method is invoked during a call to internal.setState to give all of a component's mixins and classes a chance to respond to changes in state. If one mixin/class updates state that it controls, another mixin/class may want to respond by updating some other state member that it controls.

This method should return a dictionary of changes that should be applied to the state. If the dictionary object is not empty, the internal.setState method will apply the changes to the state, and invoke this stateEffects method again to determine whether there are any third-order effects that should be applied. This process repeats until all mixins/classes report that they have no additional changes to make.

See an example of how ReactiveMixin invokes the stateEffects to ensure state consistency.

Parameters:

• state: PlainObject – a proposal for a new state
• changed: ChangedFlags – the set of fields changed in this latest proposal for the new state

Returns: PlainObject

Defined by ReactiveMixin

The "type" of the form field, provided for consistency with the native HTML type property.

If a base class provides a type property, that will be returned. (If this mixin is applied to a class defined by WrappedStandardElement, this will return the type of the inner standard element.) Otherwise, the default value of this property will be the same as the HTML tag name registered for the custom element.

Type: string

Defined by FormElementMixin

The value attribute of the selected item.

Setting this to a string will attempt to select the first list item whose value attribute matches that string. Setting this to a string not matching any value attribute will result in no selection.

Type: string

Defined by SelectedValueAPIMixin