resolve #2837 added dynamic event bindings

src/runtime/internal/Component.ts

@@ -237,6 +237,13 @@ if (typeof HTMLElement === 'function') {
 export class SvelteComponent {
 	$$: T$$;
 	$$set?: ($$props: any) => void;
+	eventBindings: any;
+
+	constructor(props) {
+		if (props && props.props && Object.prototype.hasOwnProperty.call(props.props, 'event:bindings')) {
+			this.eventBindings = props.props['event:bindings'];
+		}
+	}
 
 	$destroy() {
 		destroy_component(this, 1);

src/runtime/internal/lifecycle.ts

@@ -34,6 +34,7 @@ export function createEventDispatcher<
 
 	return (type: string, detail?: any) => {
 		const callbacks = component.$$.callbacks[type];
+		const eventBinding = component.eventBindings && Object.prototype.hasOwnProperty.call(component.eventBindings, type) ? component.eventBindings[type] : undefined;
 
 		if (callbacks) {
 			// TODO are there situations where events could be dispatched
@@ -43,6 +44,12 @@ export function createEventDispatcher<
 				fn.call(component, event);
 			});
 		}
+
+		if (eventBinding) {
+			// in a server (non-DOM) environment?
+			const event = custom_event(type, detail);
+			eventBinding.call(component, event);
+		}
 	};
 }