lazy-widgets/dist/events/WidgetEvent.d.ts

Typescript retained mode GUI for the HTML canvas API

/**
 * Which event propagation model is an event type using?
 *
 * @category Event
 */
export declare enum PropagationModel {
    /**
     * This event is propagated down the UI tree, in depth-first order. The
     * event is handled at every iterated {@link Widget}.
     */
    Trickling = 0,
    /**
     * This event is propagated down the UI tree. The event is handled at every
     * iterated {@link Widget}.
     */
    Bubbling = 1,
    /**
     * This event is only handled at the origin of the event; it does not
     * propagate.
     */
    Sticky = 2
}
/**
 * An event fired to/from a {@link Widget} in a UI tree.
 *
 * @category Event
 */
export declare abstract class WidgetEvent {
    /**
     * The type of this event class. Each event type should be unique, and have
     * a unique class.
     *
     * Due to Typescript limitations, no compile error is thrown when this
     * static field is not set at a sub-class. Despite this, the type **must**
     * be set to a unique string value.
     */
    static readonly type: string;
    /**
     * The type of this event **instance**. Compare this against the static
     * {@link WidgetEvent."type"} in the class or a known string value.
     * Comparing this value and doing an `instanceof` check must be equivalent.
     */
    abstract readonly type: string;
    /**
     * Is this event capturable by user event handlers?
     *
     * Note that if the event does not propagate, capturing the event still has
     * an effect; events are handled in the order for which the handlers were
     * added, meaning that if a handler captures the event, the other handlers
     * won't be called.
     */
    abstract readonly userCapturable: boolean;
    /** Which event propagation model is this event type using? */
    abstract readonly propagation: PropagationModel;
    /**
     * Check if the type of this event instance matches the type of a given
     * event class, asserting that the instance is of the class' type.
     */
    isa<E extends WidgetEvent>(clazz: new (...args: any[]) => E): this is E;
}