From f2931b5ff10d39131d00fbc8dd978ee56149be85 Mon Sep 17 00:00:00 2001
From: Benjamin GROENEVELD <benj.groeneveld@gmail.com>
Date: Sat, 13 Oct 2018 15:09:39 +0200
Subject: [PATCH] Fix hash link reliability (fix #434)

---
 templates/src/client/start/index.ts        |  5 +++++
 test/apps/scroll/src/routes/tall-page.html |  1 +
 test/apps/scroll/test.ts                   | 17 +++++++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/templates/src/client/start/index.ts b/templates/src/client/start/index.ts
index 17979a3b4..78beb4b40 100644
--- a/templates/src/client/start/index.ts
+++ b/templates/src/client/start/index.ts
@@ -83,6 +83,11 @@ function handle_click(event: MouseEvent) {
 	const svg = typeof a.href === 'object' && a.href.constructor.name === 'SVGAnimatedString';
 	const href = String(svg ? (<SVGAElement>a).href.baseVal : a.href);
 
+	// If we are clicking on the same hash we still want to scroll to it anyway.
+	if (location.hash && href === location.href) {
+		return;
+	}
+
 	if (href === location.href) {
 		event.preventDefault();
 		return;
diff --git a/test/apps/scroll/src/routes/tall-page.html b/test/apps/scroll/src/routes/tall-page.html
index 7e42ff94e..3a92a984b 100644
--- a/test/apps/scroll/src/routes/tall-page.html
+++ b/test/apps/scroll/src/routes/tall-page.html
@@ -1,3 +1,4 @@
+<a href="tall-page#foo">scroll to foo</a>
 <div style="height: 9999px"></div>
 
 <div id="foo">
diff --git a/test/apps/scroll/test.ts b/test/apps/scroll/test.ts
index 0c0db39b0..cf400b22c 100644
--- a/test/apps/scroll/test.ts
+++ b/test/apps/scroll/test.ts
@@ -33,6 +33,23 @@ describe('scroll', function() {
 		assert.ok(scrollY > 0, scrollY);
 	});
 
+	it('scrolls to any deeplink if it was already active', async () => {
+		await page.goto(`${base}/tall-page#foo`);
+		await start();
+
+		let scrollY = await page.evaluate(() => window.scrollY);
+		assert.ok(scrollY > 0, scrollY);
+
+		await page.evaluate(() => window.scrollTo(0, 0));
+		scrollY = await page.evaluate(() => window.scrollY);
+		assert.ok(scrollY === 0, scrollY);
+
+		await page.click('[href="tall-page#foo"]');
+		await wait(50);
+		scrollY = await page.evaluate(() => window.scrollY);
+		assert.ok(scrollY > 0, scrollY);
+	});
+
 	it('resets scroll when a link is clicked', async () => {
 		await page.goto(`${base}/tall-page#foo`);
 		await start();