remove whitespace around <:Window/> - fixes #943

src/generators/dom/preprocess.ts

@@ -449,9 +449,18 @@ function preprocessChildren(
 	const cleaned: Node[] = [];
 	let lastChild: Node;
 
+	let windowComponent;
+
 	node.children.forEach((child: Node) => {
 		if (child.type === 'Comment') return;
 
+		// special case — this is an easy way to remove whitespace surrounding
+		// <:Window/>. lil hacky but it works
+		if (child.type === 'Element' && child.name === ':Window') {
+			windowComponent = child;
+			return;
+		}
+
 		if (child.type === 'Text' && lastChild && lastChild.type === 'Text') {
 			lastChild.data += child.data;
 			lastChild.end = child.end;
@@ -502,6 +511,7 @@ function preprocessChildren(
 	}
 
 	node.children = cleaned;
+	if (windowComponent) cleaned.unshift(windowComponent);
 }
 
 export default function preprocess(

src/generators/dom/visitors/Element/meta/Window.ts

@@ -61,7 +61,7 @@ export default function visitWindow(
 			block.builders.init.addBlock(deindent`
 				function ${handlerName}(event) {
 					${handlerBody}
-				};
+				}
 				window.addEventListener("${attribute.name}", ${handlerName});
 			`);
 
@@ -121,7 +121,7 @@ export default function visitWindow(
 		block.builders.init.addBlock(deindent`
 			function ${handlerName}(event) {
 				${handlerBody}
-			};
+			}
 			window.addEventListener("${event}", ${handlerName});
 		`);
 
@@ -144,7 +144,7 @@ export default function visitWindow(
 					? `#component.get("${bindings.scrollY}")`
 					: `window.scrollY`};
 				window.scrollTo(x, y);
-			};
+			}
 		`);
 
 		if (bindings.scrollX)
@@ -172,7 +172,7 @@ export default function visitWindow(
 		block.builders.init.addBlock(deindent`
 			function ${handlerName}(event) {
 				#component.set({ ${bindings.online}: navigator.onLine });
-			};
+			}
 			window.addEventListener("online", ${handlerName});
 			window.addEventListener("offline", ${handlerName});
 		`);

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

@@ -189,7 +189,7 @@ var proto = {
 
 /* generated by Svelte vX.Y.Z */
 function create_main_fragment(state, component) {
-	var window_updating = false, text, p, text_1, text_2;
+	var window_updating = false, p, text, text_1;
 
 	function onwindowscroll(event) {
 		window_updating = true;
@@ -208,27 +208,24 @@ function create_main_fragment(state, component) {
 
 	return {
 		c: function create() {
-			text = createText("\n\n");
 			p = createElement("p");
-			text_1 = createText("scrolled to ");
-			text_2 = createText(state.y);
+			text = createText("scrolled to ");
+			text_1 = createText(state.y);
 		},
 
 		m: function mount(target, anchor) {
-			insertNode(text, target, anchor);
 			insertNode(p, target, anchor);
+			appendNode(text, p);
 			appendNode(text_1, p);
-			appendNode(text_2, p);
 		},
 
 		p: function update(changed, state) {
 			if (changed.y) {
-				text_2.data = state.y;
+				text_1.data = state.y;
 			}
 		},
 
 		u: function unmount() {
-			detachNode(text);
 			detachNode(p);
 		},
 

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, text, p, text_1, text_2;
+	var window_updating = false, p, text, text_1;
 
 	function onwindowscroll(event) {
 		window_updating = true;
@@ -11,7 +11,7 @@ function create_main_fragment(state, component) {
 			y: this.scrollY
 		});
 		window_updating = false;
-	};
+	}
 	window.addEventListener("scroll", onwindowscroll);
 
 	component.observe("y", function(y) {
@@ -21,27 +21,24 @@ function create_main_fragment(state, component) {
 
 	return {
 		c: function create() {
-			text = createText("\n\n");
 			p = createElement("p");
-			text_1 = createText("scrolled to ");
-			text_2 = createText(state.y);
+			text = createText("scrolled to ");
+			text_1 = createText(state.y);
 		},
 
 		m: function mount(target, anchor) {
-			insertNode(text, target, anchor);
 			insertNode(p, target, anchor);
+			appendNode(text, p);
 			appendNode(text_1, p);
-			appendNode(text_2, p);
 		},
 
 		p: function update(changed, state) {
 			if (changed.y) {
-				text_2.data = state.y;
+				text_1.data = state.y;
 			}
 		},
 
 		u: function unmount() {
-			detachNode(text);
 			detachNode(p);
 		},