reuse timeout function

Author: Rich-Harris

src/generators/nodes/Window.ts

@@ -107,6 +107,7 @@ export default class Window extends Node {
 		});
 
 		const lock = block.getUniqueName(`window_updating`);
+		const clear = block.getUniqueName(`clear_window_updating`);
 		const timeout = block.getUniqueName(`window_updating_timeout`);
 
 		Object.keys(events).forEach(event => {
@@ -116,7 +117,8 @@ export default class Window extends Node {
 			if (event === 'scroll') {
 				// TODO other bidirectional bindings...
 				block.addVariable(lock, 'false');
-				block.addVariable(timeout,);
+				block.addVariable(clear, `function() { ${lock} = false; }`);
+				block.addVariable(timeout);
 			}
 
 			const handlerBody = deindent`
@@ -161,7 +163,7 @@ export default class Window extends Node {
 						? `#component.get("${bindings.scrollY}")`
 						: `window.scrollY`};
 					window.scrollTo(x, y);
-					${timeout} = setTimeout(function() { ${lock} = false; }, 100);
+					${timeout} = setTimeout(${clear}, 100);
 				}
 			`);
 
@@ -181,7 +183,7 @@ export default class Window extends Node {
 					${lock} = true;
 					clearTimeout(${timeout});
 					window.scrollTo(${isX ? 'x, window.scrollY' : 'window.scrollX, y'});
-					${timeout} = setTimeout(function() { ${lock} = false; }, 100);
+					${timeout} = setTimeout(${clear}, 100);
 				});
 			`);
 		}

test/js/samples/window-binding-scroll/expected-bundle.js

@@ -190,7 +190,7 @@ var proto = {
 
 /* generated by Svelte vX.Y.Z */
 function create_main_fragment(state, component) {
-	var window_updating = false, window_updating_timeout, p, text, text_1;
+	var window_updating = false, clear_window_updating = function() { window_updating = false; }, window_updating_timeout, p, text, text_1;
 
 	function onwindowscroll(event) {
 		if (window_updating) return;
@@ -207,7 +207,7 @@ function create_main_fragment(state, component) {
 		window_updating = true;
 		clearTimeout(window_updating_timeout);
 		window.scrollTo(window.scrollX, y);
-		window_updating_timeout = setTimeout(function() { window_updating = false; }, 100);
+		window_updating_timeout = setTimeout(clear_window_updating, 100);
 	});
 
 	return {

test/js/samples/window-binding-scroll/expected.js

@@ -2,7 +2,7 @@
 import { appendNode, assign, createElement, createText, detachNode, init, insertNode, proto } from "svelte/shared.js";
 
 function create_main_fragment(state, component) {
-	var window_updating = false, window_updating_timeout, p, text, text_1;
+	var window_updating = false, clear_window_updating = function() { window_updating = false; }, window_updating_timeout, p, text, text_1;
 
 	function onwindowscroll(event) {
 		if (window_updating) return;
@@ -19,7 +19,7 @@ function create_main_fragment(state, component) {
 		window_updating = true;
 		clearTimeout(window_updating_timeout);
 		window.scrollTo(window.scrollX, y);
-		window_updating_timeout = setTimeout(function() { window_updating = false; }, 100);
+		window_updating_timeout = setTimeout(clear_window_updating, 100);
 	});
 
 	return {