fix: Hash preservation (#451)

* fix: Remove hash from base before rendering URL

* test: Add e2e test for hash preservation

packages/e2e/cypress/e2e/hash-preservation.cy.js

@@ -0,0 +1,34 @@
+/// <reference types="cypress" />
+
+function runTest() {
+  cy.contains('#hydration-marker', 'hydrated').should('be.hidden')
+  cy.get('#string_set_a').click()
+  cy.location('search').should('eq', '?string=a')
+  cy.location('hash').should('eq', '#hash')
+  cy.get('#string_clear').click()
+  cy.location('hash').should('eq', '#hash')
+}
+
+describe('hash preservation (app router)', () => {
+  it('works in standard routes', () => {
+    cy.visit('/app/useQueryState#hash')
+    runTest()
+  })
+
+  it('works in dynamic routes', () => {
+    cy.visit('/app/useQueryState/dynamic/route#hash')
+    runTest()
+  })
+})
+
+describe('hash preservation (pages router)', () => {
+  it('works in standard routes', () => {
+    cy.visit('/pages/useQueryState#hash')
+    runTest()
+  })
+
+  it('works in dynamic routes', () => {
+    cy.visit('/pages/useQueryState/dynamic/route#hash')
+    runTest()
+  })
+})

packages/nuqs/src/update-queue.ts

@@ -173,7 +173,7 @@ function flushUpdateQueue(router: Router): [URLSearchParams, null | unknown] {
       })
     } else {
       // App router
-      const url = renderURL(location.href.split('?')[0] ?? '', search)
+      const url = renderURL(location.origin + location.pathname, search)
       debug('[nuqs queue (app)] Updating url: %s', url)
       // First, update the URL locally without triggering a network request,
       // this allows keeping a reactive URL if the network is slow.
@@ -214,9 +214,10 @@ function flushUpdateQueue(router: Router): [URLSearchParams, null | unknown] {
 }
 
 function renderURL(base: string, search: URLSearchParams) {
+  const hashlessBase = base.split('#')[0] ?? ''
   const query = renderQueryString(search)
   const hash = location.hash
-  return base + query + hash
+  return hashlessBase + query + hash
 }
 
 export function compose(