From 5c8b1f071e256159baabc0ae148845ac5f4d4cc2 Mon Sep 17 00:00:00 2001
From: Andrew Jiang <andrew@buildwithfern.com>
Date: Fri, 4 Oct 2024 15:30:39 -0400
Subject: [PATCH] update unit tests

---
 .../__test__/pruneNavigationTree.test.ts      | 55 ++++++++++++++++++-
 .../navigation/utils/pruneNavigationTree.ts   |  8 +--
 .../src/navigation/utils/updatePointsTo.ts    |  3 +-
 3 files changed, 57 insertions(+), 9 deletions(-)

diff --git a/packages/fdr-sdk/src/navigation/utils/__test__/pruneNavigationTree.test.ts b/packages/fdr-sdk/src/navigation/utils/__test__/pruneNavigationTree.test.ts
index 092d2f69e5..2ec3a34327 100644
--- a/packages/fdr-sdk/src/navigation/utils/__test__/pruneNavigationTree.test.ts
+++ b/packages/fdr-sdk/src/navigation/utils/__test__/pruneNavigationTree.test.ts
@@ -59,7 +59,7 @@ describe("pruneNavigationTree", () => {
             hidden: undefined,
             overviewPageId: undefined,
             noindex: undefined,
-            pointsTo: undefined,
+            pointsTo: FernNavigation.Slug("root/page"),
         });
     });
 
@@ -88,7 +88,7 @@ describe("pruneNavigationTree", () => {
             hidden: undefined,
             overviewPageId: undefined,
             noindex: undefined,
-            pointsTo: undefined,
+            pointsTo: FernNavigation.Slug("root/page"),
         };
 
         const result = pruneNavigationTree(root, (node) => node.id !== FernNavigation.NodeId("page"));
@@ -153,6 +153,55 @@ describe("pruneNavigationTree", () => {
             icon: undefined,
             hidden: undefined,
             noindex: undefined,
+            pointsTo: FernNavigation.Slug("root/page"),
+        });
+    });
+
+    it("should not prune section even if children are pruned", () => {
+        const root: FernNavigation.NavigationNode = {
+            type: "section",
+            id: FernNavigation.NodeId("root"),
+            slug: FernNavigation.Slug("root"),
+            title: "Root",
+            overviewPageId: FernNavigation.PageId("overview.mdx"), // this is a visitable page
+            children: [
+                {
+                    type: "page",
+                    id: FernNavigation.NodeId("page"),
+                    slug: FernNavigation.Slug("root/page"),
+                    title: "Page",
+                    pageId: FernNavigation.PageId("page.mdx"),
+                    canonicalSlug: undefined,
+                    icon: undefined,
+                    hidden: undefined,
+                    noindex: undefined,
+                },
+            ],
+            collapsed: undefined,
+            canonicalSlug: undefined,
+            icon: undefined,
+            hidden: undefined,
+            noindex: undefined,
+            pointsTo: undefined,
+        };
+
+        const result = pruneNavigationTree(root, (node) => node.id !== "page");
+
+        // structuredClone should duplicate the object
+        expect(result === root).toBe(false);
+
+        expect(result).toStrictEqual({
+            type: "section",
+            id: FernNavigation.NodeId("root"),
+            slug: FernNavigation.Slug("root"),
+            overviewPageId: FernNavigation.PageId("overview.mdx"), // this is a visitable page
+            title: "Root",
+            children: [], // children is empty, but the section is still there because it has an overview page
+            collapsed: undefined,
+            canonicalSlug: undefined,
+            icon: undefined,
+            hidden: undefined,
+            noindex: undefined,
             pointsTo: undefined,
         });
     });
@@ -214,7 +263,7 @@ describe("pruneNavigationTree", () => {
             icon: undefined,
             hidden: undefined,
             noindex: undefined,
-            pointsTo: undefined,
+            pointsTo: FernNavigation.Slug("root/page"),
         });
     });
 
diff --git a/packages/fdr-sdk/src/navigation/utils/pruneNavigationTree.ts b/packages/fdr-sdk/src/navigation/utils/pruneNavigationTree.ts
index 4ff3079a41..9f516f3ab0 100644
--- a/packages/fdr-sdk/src/navigation/utils/pruneNavigationTree.ts
+++ b/packages/fdr-sdk/src/navigation/utils/pruneNavigationTree.ts
@@ -23,7 +23,7 @@ function mutablePruneNavigationTree<ROOT extends FernNavigation.NavigationNode>(
     root: ROOT,
     keep: (node: FernNavigation.NavigationNode) => boolean,
 ): ROOT | undefined {
-    const [result, deleted] = prunetree(root, {
+    const [result] = prunetree(root, {
         predicate: keep,
         getChildren: FernNavigation.getChildren,
         getPointer: (node) => node.id,
@@ -38,10 +38,8 @@ function mutablePruneNavigationTree<ROOT extends FernNavigation.NavigationNode>(
         return undefined;
     }
 
-    if (deleted.size > 0) {
-        // since the tree has been pruned, we need to update the pointsTo property
-        mutableUpdatePointsTo(result);
-    }
+    // since the tree has been pruned, we need to update the pointsTo property
+    mutableUpdatePointsTo(result);
 
     return result;
 }
diff --git a/packages/fdr-sdk/src/navigation/utils/updatePointsTo.ts b/packages/fdr-sdk/src/navigation/utils/updatePointsTo.ts
index 3e979adb9a..17b64fb1f5 100644
--- a/packages/fdr-sdk/src/navigation/utils/updatePointsTo.ts
+++ b/packages/fdr-sdk/src/navigation/utils/updatePointsTo.ts
@@ -9,7 +9,8 @@ import { followRedirect } from "./followRedirect";
 export function mutableUpdatePointsTo(input: FernNavigation.NavigationNode): void {
     FernNavigation.traverseDF(input, (node) => {
         if (FernNavigation.hasPointsTo(node)) {
-            node.pointsTo = followRedirect(node);
+            const pointsTo = followRedirect(node);
+            node.pointsTo = node.slug === pointsTo ? undefined : pointsTo;
         }
     });
 }