rewrite

src/compiler/compile/render_dom/Block.ts

@@ -4,6 +4,7 @@ import { b, x } from 'code-red';
 import { Node, Identifier, ArrayPattern } from 'estree';
 import { is_head } from './wrappers/shared/is_head';
 import { regex_double_quotes } from '../../utils/patterns';
+import { Expression } from 'estree';
 
 export interface Bindings {
 	object: Identifier;
@@ -58,6 +59,7 @@ export default class Block {
 		destroy: Array<Node | Node[]>;
 	};
 
+	event_updaters: ({condition:Expression, snippet:Node, index:number})[] = [];
 	event_listeners: Node[] = [];
 
 	maintain_context: boolean;
@@ -481,6 +483,15 @@ export default class Block {
 					`
 				);
 
+				if (this.event_updaters.length === 1) {
+					const {condition, snippet} = this.event_updaters[0];
+					this.chunks.update.push(b`
+					if (${condition}) {
+						${dispose}.swap(${snippet})
+					}`
+					);
+				}
+
 				this.chunks.destroy.push(
 					b`${dispose}();`
 				);
@@ -494,6 +505,14 @@ export default class Block {
 					}
 				`);
 
+				for (const {condition, snippet, index} of this.event_updaters) {
+					this.chunks.update.push(b`
+					if (${condition}) {
+						${dispose}[${index}].swap(${snippet})
+					}`
+					);
+				}
+
 				this.chunks.destroy.push(
 					b`@run_all(${dispose});`
 				);

src/compiler/compile/render_dom/wrappers/Element/EventHandler.ts

@@ -1,9 +1,8 @@
 import EventHandler from '../../../nodes/EventHandler';
 import Wrapper from '../shared/Wrapper';
 import Block from '../../Block';
-import { x, p, b } from 'code-red';
+import { x, p } from 'code-red';
 import { Expression } from 'estree';
-import { sanitize } from '../../../../utils/names';
 
 const TRUE = x`true`;
 const FALSE = x`false`;
@@ -67,17 +66,12 @@ export default class EventHandlerWrapper {
 		}
 
 		if (this.node.reassigned) {
-			const handle = this.node.component.get_unique_name(`${sanitize(this.node.name)}_handle`);
-			block.add_variable(handle);
-
+			const index = block.event_listeners.length;
 			const condition = block.renderer.dirty(this.node.expression.dynamic_dependencies());
 
-			block.chunks.update.push(b`
-				if (${condition}) {
-					${handle}.swap(${snippet})
-				}`);
+			block.event_updaters.push({condition, snippet, index});
 			block.event_listeners.push(
-				x`${handle} = @listen_swap(${snippet}, (h)=> ${listen}(${target}, "${this.node.name}", h, ${args}))`
+				x`@listen_swap(${snippet}, (h)=> ${listen}(${target}, "${this.node.name}", h, ${args}))`
 			);
 		} else {
 			block.event_listeners.push(

src/runtime/internal/dom.ts

@@ -264,16 +264,16 @@ export function wrap_handler(handler: EventListenerOrEventListenerObject, wrappe
 	return result;
 }
 
-export function listen(node: EventTarget, event: string, handler: EventListenerOrEventListenerObject|null|undefined, options?: boolean | AddEventListenerOptions | EventListenerOptions, wrappers?: Function[]) {
+export function listen(node: EventTarget, event: string, handler: EventListenerOrEventListenerObject|null|undefined|false, options?: boolean | AddEventListenerOptions | EventListenerOptions, wrappers?: Function[]) {
 	if (handler) {
-		handler = wrap_handler(handler, wrappers);
-		node.addEventListener(event, handler, options);
-		return () => node.removeEventListener(event, handler, options);
+		const h = wrap_handler(handler, wrappers);
+		node.addEventListener(event, h, options);
+		return () => node.removeEventListener(event, h, options);
 	}
 	return noop;
 }
 
-export function listen_swap(handler: EventListenerOrEventListenerObject|null|undefined, factory: (handler:EventListenerOrEventListenerObject) => Function) {
+export function listen_swap(handler: EventListenerOrEventListenerObject|null|undefined|false, factory: (handler:EventListenerOrEventListenerObject|null|undefined|false) => Function) {
 	let disposeHandle: Function = factory(handler);
 	const dispose = () => {
 		disposeHandle();

src/runtime/internal/lifecycle.ts

@@ -231,7 +231,7 @@ export function bubble(component: SvelteComponent, listen_func: Function, node:
 	});
 }
 
-export function listen_comp(comp: SvelteComponent, event: string, handler: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions | EventListenerOptions, wrappers?: Function[]) {
+export function listen_comp(comp: SvelteComponent, event: string, handler: EventListenerOrEventListenerObject|null|undefined|false, options?: boolean | AddEventListenerOptions | EventListenerOptions, wrappers?: Function[]) {
 	if (handler) {
 		return comp.$on(event, wrap_handler(handler, wrappers), options);
 	}