ElementController class

@microsoft/fast-element > ElementController

ElementController class

Controls the lifecycle and rendering of a FASTElement.

Signature:

export declare class ElementController<TElement extends HTMLElement = HTMLElement> implements Notifier, HostController<TElement>

Implements: Notifier, HostController<TElement>

Remarks

The constructor for this class is marked as internal. Third-party code should not call the constructor directly or create subclasses that extend the ElementController class.

Properties

Property	Modifiers	Type	Description
behaviors	`protected`	Map<HostBehavior<TElement>, number> \| null	The behaviors associated with the component.
context	`readonly`	ExecutionContext	The context the expression is evaluated against.
definition	`readonly`	FASTElementDefinition	The element definition that instructs this controller in how to handle rendering and other platform integrations.
hasExistingShadowRoot	`protected`	boolean	Indicates whether the element has an existing shadow root (e.g. from declarative shadow DOM).
isBound	`readonly`	boolean	Indicates whether the controller is bound.
isConnected	`readonly`	boolean	Indicates whether or not the custom element has been connected to the document.
isHydrated	`readonly`	Promise<boolean>	Resolves `true` after prerendered content has been successfully hydrated, or `false` when the component is client-side rendered or hydration is not enabled.
isPrerendered	`readonly`	Promise<boolean>	Resolves `true` when the element had an existing shadow root (from SSR or declarative shadow DOM) at connect time, `false` otherwise.
mainStyles		ElementStyles \| null	The main set of styles used for the component, independent of any dynamically added styles.
needsInitialization	`protected`	boolean	Indicates whether the controller needs to perform initial rendering.
shadowOptions		ShadowRootOptions \| undefined	The shadow root options for the component.
source	`readonly`	TElement	The element being controlled by this controller.
sourceLifetime	`readonly`	SourceLifetime \| undefined	Indicates how the source's lifetime relates to the controller's lifetime.
stage	`protected`	Stages	The current lifecycle stage of the controller.
subject	`readonly`	TElement	The subject that subscribers will receive notifications for.
template		ElementViewTemplate<TElement> \| null	Gets/sets the template used to render the component.
view	`readonly`	ElementView<TElement> \| null	The view associated with the custom element.

Methods

Method	Modifiers	Description
addBehavior(behavior)		Adds the behavior to the component.
addStyles(styles)		Adds styles to this element. Providing an HTMLStyleElement will attach the element instance to the shadowRoot.
bindObservables()	`protected`	Binds any observables that were set before upgrade.
captureBoundObservables()	`protected`	Captures own-properties that shadow observable accessors on the prototype so they can be rebound through the accessor before rendering.
connect()		Runs connected lifecycle behavior on the associated element.
connectBehaviors()	`protected`	Connects any existing behaviors on the associated element.
disconnect()		Runs disconnected lifecycle behavior on the associated element.
disconnectBehaviors()	`protected`	Disconnects any behaviors on the associated element.
emit(type, detail, options)		Emits a custom HTML event.
forCustomElement(element, override)	`static`	Locates or creates a controller for the specified element.
notify(args)		Notifies all subscribers of a property change.
observeLateAttributes()	`protected`	Observes late-defined attribute-map attributes that the platform does not surface through attributeChangedCallback because they were added after customElements.define() completed.
onAttributeChangedCallback(name, oldValue, newValue)		Runs the attribute changed callback for the associated element.
onUnbind(behavior)		Registers an unbind handler with the controller.
removeBehavior(behavior, force)		Removes the behavior from the component.
removeStyles(styles)		Removes styles from this element. Providing an HTMLStyleElement will detach the element instance from the shadowRoot.
renderTemplate(template)	`protected`	Renders the provided template to the element.
setStrategy(strategy)	`static`	Sets the strategy that ElementController.forCustomElement uses to construct ElementController instances for an element.
subscribe(subscriber, propertyToWatch)		Subscribes to notification of changes in the element's state.
syncLateAttributes()	`protected`	Synchronizes late-defined attribute-map attributes from the live DOM to the associated property values before the initial render occurs.
unsubscribe(subscriber, propertyToUnwatch)		Unsubscribes from notification of changes in the element's state.