fix(gatsby): Fix truncation of childNode during static HTML generation (

#36704) (#36717)

* use innertext of node and not first node text content

* use node "text"

* add test

* remove logs

* use textcontext

(cherry picked from commit ad1148e)

Co-authored-by: Jude Agboola <marvinjudehk@gmail.com>

integration-tests/head-function-export/__tests__/ssr-html-output.js

@@ -29,7 +29,8 @@ describe(`Head function export SSR'ed HTML output`, () => {
     const { base, title, meta, noscript, style, link, jsonLD } = getNodes(dom)
 
     expect(base.attributes.href).toEqual(data.static.base)
-    expect(title.text).toEqual(data.static.title)
+    //Intentionally duplicate the title to test that we don't strip out multiple text nodes
+    expect(title.text).toEqual(`${data.static.title} ${data.static.title}`)
     expect(meta.attributes.content).toEqual(data.static.meta)
     expect(noscript.text).toEqual(data.static.noscript)
     expect(style.text).toContain(data.static.style)

integration-tests/head-function-export/src/pages/head-function-export/basic.js

@@ -20,7 +20,7 @@ export function Head() {
   return (
     <>
       <base data-testid="base" href={base} />
-      <title data-testid="title">{title}</title>
+      <title data-testid="title">{title} {title}</title>
       <meta data-testid="meta" name="author" content={meta} />
       <noscript data-testid="noscript">{noscript}</noscript>
       <style data-testid="style">

packages/gatsby/cache-dir/head/head-export-handler-for-ssr.js

@@ -74,11 +74,14 @@ export function headHandlerForSSR({
             />
           )
         } else {
-          element = (
-            <node.rawTagName {...attributes}>
-              {node.childNodes[0]?.textContent}
-            </node.rawTagName>
-          )
+          element =
+            node.textContent.length > 0 ? (
+              <node.rawTagName {...attributes}>
+                {node.textContent}
+              </node.rawTagName>
+            ) : (
+              <node.rawTagName {...attributes} />
+            )
         }
 
         if (id) {