Fix client side router issue with handling hash (#3757)

Author: PH4NTOMiki

.changeset/chatty-ducks-shop.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Prevent full reload when router navigates and only removes hash

packages/kit/src/runtime/client/router.js

@@ -184,8 +184,11 @@ export class Router {
 			// Ignore if <a> has a target
 			if (a instanceof SVGAElement ? a.target.baseVal : a.target) return;
 
-			// Check if new url only differs by hash
-			if (url.href.split('#')[0] === location.href.split('#')[0]) {
+			// Check if new url only differs by hash and use the browser default behavior in that case
+			// This will ensure the `hashchange` event is fired
+			// Removing the hash does a full page navigation in the browser, so make sure a hash is present
+			const [base, hash] = url.href.split('#');
+			if (hash && base === location.href.split('#')[0]) {
 				// Call `pushState` to add url to history so going back works.
 				// Also make a delay, otherwise the browser default behaviour would not kick in
 				setTimeout(() => history.pushState({}, '', url.href));