Fix broken links with structure-dir router

Resolves #2928

Author: Gerrit0

CHANGELOG.md

@@ -20,6 +20,7 @@ title: Changelog
 - When printing entry point globs which fail to match any paths, TypeDoc will no longer normalize the glob, #2918.
 - Inlining types can now handle more type variants, #2920.
 - Fixed behavior of `externalSymbolLinkMappings` option when URL is set to `#`, #2921.
+- Fixed broken links within module pages when structure-dir router was used, #2928.
 - API: `toString` on types containing index signatures now behave correctly, #2917.
 
 ## v0.28.1 (2025-03-20)

src/lib/output/router.ts

@@ -221,6 +221,19 @@ export abstract class BaseRouter implements Router {
  // an own document.
  from = from.parent as RouterTarget;
  }
+
+ let toPage = to;
+ while (!this.hasOwnDocument(toPage)) {
+ toPage = toPage.parent as RouterTarget;
+ }
+
+ // We unfortunately have to special case ProjectReflection as it is
+ // the model used twice for rendering. This should be changed in a
+ // future version to remove this hackery.
+ if (from === toPage && !(to instanceof ProjectReflection)) {
+ return to === toPage ? "" : `#${this.getAnchor(to)}`;
+ }
+
  const fromUrl = this.getFullUrl(from);
  const toUrl = this.getFullUrl(to);
  let equal = true;
@@ -237,13 +250,15 @@ export abstract class BaseRouter implements Router {
  }
  }
 
- if (equal && !(to instanceof ProjectReflection)) {
-  if (fromUrl === toUrl) {
-  return "";
-  }
- return `#${this.getAnchor(to)}`;
+ // If equal is still set, we're going to a page either in
+ // the same directory as this page, or a lower directory,
+ // don't bother going up directories just to come back down.
+ if (equal) {
+ return toUrl.substring(start);
  }
 
+ // Otherwise, go up until we get to the common directory
+ // and then back down to the target path.
  return "../".repeat(slashes) + toUrl.substring(start);
  }
 

src/test/output/router.test.ts

@@ -330,6 +330,16 @@ describe("StructureDirRouter", () => {
  ),
  "../../Foo/#codegeneration",
  );
+
+ equal(
+ router.relativeUrl(
+ query(project, "Nested"),
+ query(project, "Nested.refl"),
+ ),
+ "refl/",
+ );
+
+ equal(router.relativeUrl(query(project, "Nested.refl"), query(project, "Nested")), "../");
  });
 });