preserve Azure and Snowflake sidebar context on detail pages (#475)

Author: HarshCasper

src/routeData.ts

@@ -1,7 +1,70 @@
 import { defineRouteMiddleware } from '@astrojs/starlight/route-data';
 
 export const onRequest = defineRouteMiddleware((context) => {
-  const { starlightRoute } = context.locals;
+  const locals = context.locals as typeof context.locals & {
+    starlightUtils?: {
+      multiSidebar?: any[];
+    };
+  };
+  const { starlightRoute } = locals;
+
+  const pathname = context.url.pathname.replace(/\/+$/, '') || '/';
+  const sidebarContextOverrides = [
+    {
+      match: /^\/azure\/services\/[^/]+$/,
+      sidebarLabel: 'Azure',
+      currentLinkHref: '/azure/services/',
+    },
+    {
+      match: /^\/snowflake\/features\/[^/]+$/,
+      sidebarLabel: 'Snowflake',
+      currentLinkHref: '/snowflake/features/',
+    },
+  ];
+  const sidebarContextOverride = sidebarContextOverrides.find(({ match }) =>
+    match.test(pathname)
+  );
+
+  if (sidebarContextOverride) {
+    const { sidebarLabel, currentLinkHref } = sidebarContextOverride;
+
+    const markLinkCurrent = (entry: any): boolean => {
+      if (entry.type === 'link' && entry.href === currentLinkHref) {
+        entry.isCurrent = true;
+        return true;
+      }
+      if (entry.type === 'group') {
+        return entry.entries.some((nestedEntry: any) => markLinkCurrent(nestedEntry));
+      }
+      return false;
+    };
+
+    const resetGroupCurrentState = (entry: any) => {
+      if (entry.type === 'link') {
+        entry.isCurrent = false;
+        return;
+      }
+      if (entry.type === 'group') {
+        entry.entries.forEach((nestedEntry: any) => resetGroupCurrentState(nestedEntry));
+      }
+    };
+
+    for (const entry of starlightRoute.sidebar) {
+      if (entry.type !== 'group') continue;
+      if (entry.label === sidebarLabel) {
+        markLinkCurrent(entry);
+      } else {
+        resetGroupCurrentState(entry);
+      }
+    }
+
+    const multiSidebarData = locals.starlightUtils?.multiSidebar;
+    if (Array.isArray(multiSidebarData)) {
+      multiSidebarData.forEach((data: any) => {
+        data.isCurrentSidebar = data.label?.label === sidebarLabel;
+      });
+    }
+  }
 
   const overviewItem = starlightRoute.toc?.items[0];
   if (overviewItem) overviewItem.text = 'Back to top';