fix: stream solid suspense chunks independently

e2e/solid-start/basic-test-suite/src/streaming.spec.ts

@@ -27,6 +27,22 @@ test('Directly visiting the deferred route', async ({ page }) => {
   )
 })
 
+test('deferred route streams boundaries independently', async ({ page }) => {
+  await page.goto('/deferred', { waitUntil: 'commit' })
+
+  await expect(page.getByTestId('regular-person')).toContainText('John Doe')
+  await expect(page.getByText('Loading person...')).toBeVisible()
+  await expect(page.getByText('Loading stuff...')).toBeVisible()
+
+  await expect(page.getByTestId('deferred-person')).toContainText(
+    'Tanner Linsley',
+  )
+  await expect(page.getByText('Loading stuff...')).toBeVisible()
+  await expect(page.getByTestId('deferred-stuff')).toContainText(
+    'Hello deferred!',
+  )
+})
+
 test('streaming loader data', async ({ page }) => {
   await page.goto('/stream')
 

packages/router-core/src/ssr/transformStreamWithRouter.ts

@@ -227,7 +227,9 @@ export function transformStreamWithRouter(
   // between-chunk text buffer; keep bounded to avoid unbounded memory
   let leftover = ''
 
-  // captured closing tags from </body> onward
+  // Captured closing tags that must stay after router-injected scripts.
+  // Some renderers, like Solid, continue streaming boundary chunks after
+  // </html>; those chunks should still pass through before these tags.
   let pendingClosingTags = ''
 
   // conservative cap: enough to hold any partial closing tag + a bit
@@ -404,9 +406,11 @@ export function transformStreamWithRouter(
           }
         }
 
-        // If we already saw </body>, everything else is part of tail; buffer it.
+        // If we already saw </body>, keep streaming app chunks before the
+        // captured closing tags instead of buffering them until render end.
         if (pendingClosingTags) {
-          pendingClosingTags += chunkString
+          flushPendingRouterHtml()
+          safeEnqueue(chunkString)
           leftover = ''
           continue
         }
@@ -419,9 +423,11 @@ export function transformStreamWithRouter(
           htmlEndIndex !== -1 &&
           bodyEndIndex < htmlEndIndex
         ) {
-          pendingClosingTags = chunkString.slice(bodyEndIndex)
+          const htmlEndTagEnd = htmlEndIndex + HTML_END_TAG.length
+          pendingClosingTags = chunkString.slice(bodyEndIndex, htmlEndTagEnd)
           safeEnqueue(chunkString.slice(0, bodyEndIndex))
           flushPendingRouterHtml()
+          safeEnqueue(chunkString.slice(htmlEndTagEnd))
           leftover = ''
           continue
         }