Title a one page export with the site name on the path the editor uses

src/__tests__/exportPages.test.ts

@@ -197,6 +197,16 @@ describe("the browser tab says what the site is called", () => {
     expect(body.html).toContain('<meta property="og:title" content="Riverbank Books" />');
   });
 
+  it("titles a one page site sent the way the editor sends it", async () => {
+    // The editor posts a page list, and its lone page is called Home. Fixing only the
+    // sections path left every export made in the editor saying Home in the tab.
+    const { body } = await exportSite({
+      pages: [{ slug: HOME_SLUG, title: "Home", sections: kept.sections }],
+      siteName: "Riverbank Books",
+    });
+    expect(body.html).toContain("<title>Riverbank Books</title>");
+  });
+
   it("still titles each page of a real site with its own name", async () => {
     const { body } = await exportSite({ pages: threePages, siteName: "Northgate" });
     expect(body.pages[0].html).toContain("<title>Home</title>");

src/app/api/export-site/route.ts

@@ -210,10 +210,7 @@ export async function POST(req: NextRequest) {
      */
     let sitePages: SitePage[];
     if (pages === undefined || pages === null) {
-      // A site of one page is titled by the site's own name. asPages calls it "Home",
-      // which is right in a nav beside About and Contact, and wrong in the browser tab
-      // and the share card of a site that has no other page.
-      sitePages = asPages({ sections: validSections }).map((page) => ({ ...page, title: siteName || page.title }));
+      sitePages = asPages({ sections: validSections });
     } else {
       const parsedPages = pagesSchema.safeParse(pages);
       if (!parsedPages.success) {
@@ -227,6 +224,19 @@ export async function POST(req: NextRequest) {
       }
     }
 
+    /**
+     * A site of one page is titled by the site's own name.
+     *
+     * Both the editor and `asPages` call a lone page "Home", which is right in a nav
+     * beside About and Contact and wrong in the browser tab and the share card of a site
+     * that has no other page. Applied here rather than on one of the two paths in, which
+     * is the mistake the first version of this made: the API stopped saying Home and the
+     * editor, which is how everybody actually exports, carried on.
+     */
+    if (sitePages.length === 1 && siteName) {
+      sitePages = [{ ...sitePages[0], title: siteName }];
+    }
+
     const emptyPage = sitePages.find((page) => onlyVisible(page.sections as Section[]).length === 0);
     if (emptyPage) {
       return NextResponse.json(