handle tag click from another page

templates/src/client/app.ts

@@ -106,18 +106,17 @@ export function scroll_state() {
 	};
 }
 
-export function navigate(target: Target, id: number, noscroll = false): Promise<any> {
+export function navigate(target: Target, id: number, scroll_to?: ScrollPosition | string): Promise<any> {
+	let scroll: ScrollPosition | string;
 	if (id) {
 		// popstate or initial navigation
 		cid = id;
+		scroll = scroll_to ? scroll_to : scroll_history[id];
 	} else {
-		const current_scroll = scroll_state();
-
 		// clicked on a link. preserve scroll state
-		scroll_history[cid] = current_scroll;
-
+		scroll_history[cid] = scroll_state();
 		id = cid = ++uid;
-		scroll_history[cid] = noscroll ? current_scroll : { x: 0, y: 0 };
+		scroll = scroll_to ? scroll_to : { x: 0, y: 0 };
 	}
 
 	cid = id;
@@ -137,13 +136,12 @@ export function navigate(target: Target, id: number, noscroll = false): Promise<
 		if (redirect) {
 			return goto(redirect.location, { replaceState: true });
 		}
-
-		render(data, nullable_depth, scroll_history[id], token);
+		render(data, nullable_depth, scroll, token);
 		if (document.activeElement) document.activeElement.blur();
 	});
 }
 
-function render(data: any, nullable_depth: number, scroll: ScrollPosition, token: {}) {
+function render(data: any, nullable_depth: number, scroll: ScrollPosition | string, token: {}) {
 	if (current_token !== token) return;
 
 	if (root_component) {
@@ -183,7 +181,18 @@ function render(data: any, nullable_depth: number, scroll: ScrollPosition, token
 	}
 
 	if (scroll) {
-		scrollTo(scroll.x, scroll.y);
+		let scrollPos: ScrollPosition;
+		if (typeof scroll === 'string') {
+			// scroll is an element id (from a hash), we need to compute y.
+			const deep_linked = document.getElementById(scroll);
+			scrollPos = deep_linked ?
+				{ x: 0, y: deep_linked.getBoundingClientRect().top } :
+				scroll_state();
+		} else {
+			scrollPos = scroll;
+		}
+		scroll_history[cid] = scrollPos;
+		scrollTo(scrollPos.x, scrollPos.y);
 	}
 
 	Object.assign(root_props, data);

templates/src/client/start/index.ts

@@ -13,7 +13,7 @@ import {
 	set_cid
 } from '../app';
 import prefetch from '../prefetch/index';
-import { Store } from '../types';
+import { Store, ScrollPosition } from '../types';
 
 export default function start(opts: {
 	target: Node,
@@ -35,17 +35,13 @@ export default function start(opts: {
 
 	return Promise.resolve().then(() => {
 		const { hash, href } = location;
-
-		const deep_linked = hash && document.getElementById(hash.slice(1));
-		scroll_history[uid] = deep_linked ?
-			{ x: 0, y: deep_linked.getBoundingClientRect().top } :
-			scroll_state();
+		const scroll_to = hash ? hash.slice(1) : scroll_state();
 
 		history.replaceState({ id: uid }, '', href);
 
 		if (!initial_data.error) {
 			const target = select_route(new URL(location.href));
-			if (target) return navigate(target, uid);
+			if (target) return navigate(target, uid, scroll_to);
 		}
 	});
 }
@@ -104,7 +100,16 @@ function handle_click(event: MouseEvent) {
 	const target = select_route(url);
 	if (target) {
 		const noscroll = a.hasAttribute('sapper-noscroll');
-		navigate(target, null, noscroll);
+		let scroll_to: ScrollPosition | string;
+		if (noscroll) {
+			scroll_to = scroll_state();
+		} else if (url.hash) {
+			scroll_to = url.hash.slice(1);
+		} else {
+			scroll_to = { x: 0, y: 0 };
+		}
+
+		navigate(target, null, scroll_to);
 		event.preventDefault();
 		history.pushState({ id: cid }, '', url.href);
 	}

test/apps/scroll/src/routes/another-tall-page.html

@@ -1 +1,2 @@
-<div style="height: 9999px"></div>
+<div style="height: 9999px"></div>
+<p id="bar">element</p>

test/apps/scroll/src/routes/tall-page.html

@@ -3,4 +3,21 @@
 <div id="foo">
 	<a href="another-tall-page">link</a>
 	<a href="another-tall-page" sapper-noscroll>link</a>
-</div>
+	{#if barLink}
+		<a href="another-tall-page#bar">link</a>
+	{/if}
+</div>
+
+<script>
+	export default {
+		data() {
+			return {
+				barLink: false
+			};
+		},
+
+		oncreate() {
+			this.set({ barLink: true })
+		}
+	}
+</script>

test/apps/scroll/test.ts

@@ -59,4 +59,16 @@ describe('scroll', function() {
 
 		assert.ok(scrollY > 0);
 	});
+
+	it('scrolls into a deeplink on a new page', async () => {
+		await page.goto(`${base}/tall-page#foo`);
+		await start();
+		await prefetchRoutes();
+
+		await page.click('[href="another-tall-page#bar"]');
+		await wait(50);
+
+		const scrollY = await page.evaluate(() => window.scrollY);
+		assert.ok(scrollY > 0);
+	});
 });