don't grab page offsets too early

src/compiler/compile/render-dom/wrappers/Window.ts

@@ -92,10 +92,10 @@ export default class WindowWrapper extends Wrapper {
 
 				renderer.meta_bindings.add_block(deindent`
 					if (${condition}) {
-						@_scrollTo(${x || '@_pageXOffset'}, ${y || '@pageYOffset'});
+						@_scrollTo(${x || '@_window.pageXOffset'}, ${y || '@_window.pageYOffset'});
 					}
-					${x && `${x} = @_pageXOffset;`}
-					${y && `${y} = @_pageYOffset;`}
+					${x && `${x} = @_window.pageXOffset;`}
+					${y && `${y} = @_window.pageYOffset;`}
 				`);
 
 				block.event_listeners.push(deindent`
@@ -148,9 +148,9 @@ export default class WindowWrapper extends Wrapper {
 					${scrolling} = true;
 					@_clearTimeout(${scrolling_timeout});
 					@_scrollTo(${
-						bindings.scrollX ? `ctx.${bindings.scrollX}` : `@_pageXOffset`
+						bindings.scrollX ? `ctx.${bindings.scrollX}` : `@_window.pageXOffset`
 					}, ${
-						bindings.scrollY ? `ctx.${bindings.scrollY}` : `@_pageYOffset`
+						bindings.scrollY ? `ctx.${bindings.scrollY}` : `@_window.pageYOffset`
 					});
 					${scrolling_timeout} = @_setTimeout(${clear_scrolling}, 100);
 				}

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

@@ -42,7 +42,7 @@ function create_fragment(ctx) {
 			if (changed.y && !scrolling) {
 				scrolling = true;
 				clearTimeout(scrolling_timeout);
-				scrollTo(pageXOffset, ctx.y);
+				scrollTo(window.pageXOffset, ctx.y);
 				scrolling_timeout = setTimeout(clear_scrolling, 100);
 			}