Preserve QWord internal hyperlinks in DOCX

src/io/wordOffice.ts

@@ -89,6 +89,7 @@ type DocxModule = {
   TextRun: new (options: string | Record<string, unknown>) => unknown;
   WidthType?: Record<string, string>;
   ExternalHyperlink?: new (options: { children: unknown[]; link: string }) => unknown;
+  InternalHyperlink?: new (options: { children: unknown[]; anchor: string }) => unknown;
   ImageRun?: new (options: Record<string, unknown>) => unknown;
 };
 
@@ -391,7 +392,17 @@ function wordInlineRunToTextRunOption(run: WordInlineRun) {
 function wordInlineRunsToTextRuns(runs: WordInlineRun[], docx: DocxModule) {
   const normalizedRuns = runs.length > 0 ? runs : [{ text: "" }];
   return normalizedRuns.flatMap((run) => {
-    const href = normalizedHyperlinkTarget(run.href);
+    const internalAnchor = normalizedInternalHyperlinkAnchor(run.href);
+    if (internalAnchor && docx.InternalHyperlink) {
+      return [
+        new docx.InternalHyperlink({
+          anchor: internalAnchor,
+          children: wordInlineRunToTextRunsForRun(run, docx, { style: "Hyperlink" })
+        })
+      ];
+    }
+
+    const href = normalizedExternalHyperlinkTarget(run.href);
     if (href && docx.ExternalHyperlink) {
       return [
         new docx.ExternalHyperlink({
@@ -842,8 +853,10 @@ function orderedDocxParagraphInlineRecords(paragraph: unknown, hyperlinkTargets:
       return [];
     }
 
-    const relationshipId = docxAttribute(orderedElementAttributes(child), "r:id") || docxAttribute(orderedElementAttributes(child), "id");
-    const href = normalizedHyperlinkTarget(hyperlinkTargets[relationshipId]);
+    const attributes = orderedElementAttributes(child);
+    const relationshipId = docxAttribute(attributes, "r:id") || docxAttribute(attributes, "id");
+    const anchor = normalizedDocxAnchor(docxAttribute(attributes, "w:anchor") || docxAttribute(attributes, "anchor"));
+    const href = normalizedExternalHyperlinkTarget(hyperlinkTargets[relationshipId]) || (anchor ? `#${anchor}` : "");
     return orderedDirectElements(child, "w:r").map((run) => ({
       run: orderedElementToRecord(run),
       text: orderedDocxRunText(run),
@@ -884,7 +897,7 @@ function docxRelationshipTargetsById(relationshipsXml: unknown) {
     }
 
     if (type === wordHyperlinkRelationshipType) {
-      const normalizedTarget = normalizedHyperlinkTarget(target);
+      const normalizedTarget = normalizedExternalHyperlinkTarget(target);
       if (normalizedTarget) {
         targets.hyperlinks[id] = normalizedTarget;
       }
@@ -1430,6 +1443,15 @@ function cssFontFamilyValue(value: string) {
 }
 
 function normalizedHyperlinkTarget(value?: string | null) {
+  const internalHref = normalizedInternalHyperlinkHref(value);
+  if (internalHref) {
+    return internalHref;
+  }
+
+  return normalizedExternalHyperlinkTarget(value);
+}
+
+function normalizedExternalHyperlinkTarget(value?: string | null) {
   const raw = value?.trim();
   if (!raw) {
     return "";
@@ -1444,6 +1466,21 @@ function normalizedHyperlinkTarget(value?: string | null) {
   }
 }
 
+function normalizedInternalHyperlinkHref(value?: string | null) {
+  const anchor = normalizedInternalHyperlinkAnchor(value);
+  return anchor ? `#${anchor}` : "";
+}
+
+function normalizedInternalHyperlinkAnchor(value?: string | null) {
+  const raw = value?.trim();
+  return raw?.startsWith("#") ? normalizedDocxAnchor(raw.slice(1)) : "";
+}
+
+function normalizedDocxAnchor(value?: string | null) {
+  const normalized = value?.trim() ?? "";
+  return /^[A-Za-z_][A-Za-z0-9_.:-]{0,79}$/.test(normalized) ? normalized : "";
+}
+
 function imageBlockFromElement(element: Element): WordImageBlock {
   return {
     type: "image",