Keep the space menu open when a space is picked from its rail

AGENTS.md

@@ -194,6 +194,7 @@ return a `Command`, so `.then(publish)` is usually all you need.
 - Use `$state.snapshot` if calling component might unmount
 - Navigate with `navigate` from `app/modal.ts` rather than `goto` — an open modal owns the current
   history entry, so a navigation that drops it replaces that entry instead of stacking on it
+- Pass `keepModal` to `navigate` to change the page under a modal and leave it open
 
 ## Development Workflow
 

e2e/specs/routing.spec.ts

@@ -146,3 +146,39 @@ test("takes over the space menu's history entry when you navigate out of it", as
   await expect(page).toHaveURL(new RegExp(`${roomPath(space.url, "lounge")}$`))
   await expect(drawer).toHaveCount(0)
 })
+
+test("switches spaces inside the space menu without closing it", async ({seed, as}) => {
+  const scenario = await seed(({relay, user}) => {
+    const space = relay("space")
+    const other = relay("other")
+
+    space.room("lounge", {name: "Space Lounge"})
+    other.room("garden", {name: "Other Garden"})
+    space.join(user.alice, "lounge")
+    other.join(user.alice, "garden")
+  })
+
+  const space = scenario.space("space")
+  const other = scenario.space("other")
+  const page = await as(users.alice, roomPath(space.url, "lounge"), {
+    context: {viewport: {width: 390, height: 844}, hasTouch: true},
+  })
+
+  const drawer = page.locator(".drawer")
+
+  await page.getByRole("button", {name: "Open space menu"}).click()
+
+  await expect(drawer.getByRole("link", {name: "Space Lounge"})).toBeVisible()
+
+  // The rail is in the menu on a phone, so a space is picked with the menu still open and the room
+  // is picked after it. Navigating out from under the menu would close it on the first tap.
+  await drawer.locator('.primary-nav [data-tip^="other"]').click()
+
+  await expect(page).toHaveURL(new RegExp(spacePath(other.url)))
+  await expect(drawer.getByRole("link", {name: "Other Garden"})).toBeVisible()
+
+  await drawer.getByRole("link", {name: "Other Garden"}).click()
+
+  await expect(page).toHaveURL(new RegExp(`${roomPath(other.url, "garden")}$`))
+  await expect(drawer).toHaveCount(0)
+})

src/app/components/PrimaryNavItemSpace.svelte

@@ -17,7 +17,7 @@
   const onClick = () => {
     const entryPath = makeSpaceEntryPath(url)
 
-    navigate(entryPath, {replaceState: entryPath === $page.url.pathname})
+    navigate(entryPath, {keepModal: true, replaceState: entryPath === $page.url.pathname})
   }
 
   const path = makeSpacePath(url)

src/app/components/SpaceMenuDrawer.svelte

@@ -3,6 +3,7 @@
   import SecondaryNav from "@lib/components/SecondaryNav.svelte"
   import SpaceMenu from "@app/components/SpaceMenu.svelte"
   import PrimaryNavSpaces from "@app/components/PrimaryNavSpaces.svelte"
+  import {lastSpaceUrl} from "@app/routes"
 
   type Props = {
     url: string
@@ -10,6 +11,8 @@
 
   const {url}: Props = $props()
 
+  const activeUrl = $derived($lastSpaceUrl ?? url)
+
   const duration = 200
 
   const parallax = 10
@@ -32,7 +35,9 @@
   </div>
   <div class="flex w-0 min-w-0 grow" in:translate={slide(parallax)} out:translate={slide(0)}>
     <SecondaryNav visible class="secondary-nav--mobile-space mt-0 h-full w-0 min-w-0 grow pb-0">
-      <SpaceMenu {url} mobile />
+      {#key activeUrl}
+        <SpaceMenu url={activeUrl} mobile />
+      {/key}
     </SecondaryNav>
   </div>
 </div>

src/app/modal.ts

@@ -64,8 +64,19 @@ const closesModal = (path: string) => {
   return hash !== "" && !path.endsWith(hash)
 }
 
-export const navigate = (path: string, options?: Parameters<typeof goto>[1]) =>
-  goto(path, {...options, replaceState: options?.replaceState || closesModal(path)})
+export type NavigateOptions = Parameters<typeof goto>[1] & {keepModal?: boolean}
+
+// The modal hash is written with the History API, so it never reaches `page` — carrying it onto
+// the path is what navigates underneath an open modal rather than closing it
+export const navigate = (path: string, {keepModal, ...options}: NavigateOptions = {}) => {
+  const hash = get(modalHash)
+
+  if (keepModal && hash) {
+    return goto(path + hash, {...options, replaceState: true})
+  }
+
+  return goto(path, {...options, replaceState: options.replaceState || closesModal(path)})
+}
 
 export const modalStack = deriveDeduplicated([modalHash, modals], ([$hash, $modals]) => {
   return getIdsFromHash($hash)