@microsoft/fast-element > HTMLBindingDirective

HTMLBindingDirective class

The central binding directive that bridges data expressions and DOM updates.

HTMLBindingDirective fulfills three roles simultaneously: - **HTMLDirective**: Produces placeholder HTML via createHTML() during template authoring. - **ViewBehaviorFactory**: Creates behaviors (returns itself) during view creation. - **ViewBehavior / EventListener**: Attaches to a DOM node during bind, manages expression observers for reactive updates, and handles DOM events directly.

The aspectType (set by HTMLDirective.assignAspect during template processing) determines which DOM "sink" function is used to apply values — e.g., setAttribute for attributes, addEventListener for events, textContent for content.

Signature:

export declare class HTMLBindingDirective implements HTMLDirective, ViewBehaviorFactory, ViewBehavior, Aspected, BindingDirective

Implements: HTMLDirective, ViewBehaviorFactory, ViewBehavior, Aspected, BindingDirective

Constructors

Constructor	Modifiers	Description
(constructor)(dataBinding)		Creates an instance of HTMLBindingDirective.

Properties

Property	Modifiers	Type	Description
aspectType		DOMAspect	The type of aspect to target.
dataBinding		Binding
id		string	The unique id of the factory.
policy		DOMPolicy	The policy that the created behavior must run under.
sourceAspect		string	The original source aspect exactly as represented in markup.
targetAspect		string	The evaluated target aspect, determined after processing the source.
targetNodeId		string	The structural id of the DOM node to which the created behavior will apply.
targetTagName		string | null	The tagname associated with the target node.

Methods

Method	Modifiers	Description
createBehavior()		Creates a behavior.
createHTML(add)		Creates HTML to be used within a template.