Preserve QPowerPoint hidden slides in PPTX

src/io/powerPointOffice.ts

@@ -24,6 +24,14 @@ type ZipEntry = {
   async(type: "base64"): Promise<string>;
 };
 type ZipArchive = { files?: Record<string, unknown>; file: (path: string) => ZipEntry | null };
+type WritableZipArchive = {
+  file: {
+    (path: string): ZipEntry | null;
+    (path: string, data: string): WritableZipArchive;
+  };
+  generateAsync: (options: { type: "blob"; mimeType: string }) => Promise<Blob>;
+};
+type ZipConstructor = { loadAsync: (data: ArrayBuffer) => Promise<WritableZipArchive> };
 
 const slidePathPattern = /^ppt\/slides\/slide(\d+)\.xml$/;
 const slideRelationshipType = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/slide";
@@ -66,6 +74,7 @@ export async function importPptxFile(file: File): Promise<ImportedPowerPointDeck
         ? extractOrderedTextBodyTexts(orderedParser.parse(notesXml)).join("\n") || extractTextBlocks(parser.parse(notesXml)).join("\n")
         : "";
       const backgroundColor = slideBackgroundColor(parsedSlide);
+      const hidden = slideHidden(parsedSlide);
 
       return {
         id: `pptx-slide-${index}`,
@@ -73,6 +82,7 @@ export async function importPptxFile(file: File): Promise<ImportedPowerPointDeck
         subtitle: slideTextBlocks.slice(1).map((block) => block.text).join("\n"),
         notes,
         theme: "classic" as const,
+        ...(hidden ? { hidden } : {}),
         ...(backgroundColor ? { backgroundColor } : {}),
         ...(slideTextBlocks[0]?.color ? { titleColor: slideTextBlocks[0].color } : {}),
         ...(slideTextBlocks[0]?.fontSize ? { titleFontSize: slideTextBlocks[0].fontSize } : {}),
@@ -169,7 +179,8 @@ export async function exportPptxBlob(deck: ExportablePowerPointDeck): Promise<Bl
   }
 
   const result = await pptx.write({ outputType: "blob" });
-  return result instanceof Blob ? result : new Blob([result], { type: PPTX_MIME_TYPE });
+  const blob = result instanceof Blob ? result : new Blob([result], { type: PPTX_MIME_TYPE });
+  return deck.slides.some((slide) => slide.hidden) ? applyHiddenSlidesToPptxBlob(blob, deck.slides) : blob;
 }
 
 export function extractTextBlocks(xmlNode: unknown): string[] {
@@ -448,6 +459,38 @@ function slideBackgroundColor(slideXml: unknown) {
   return normalizeHexColor(stringValue(srgbColor.val ?? srgbColor["@_val"]));
 }
 
+function slideHidden(slideXml: unknown) {
+  const slide = childRecord(slideXml, "sld");
+  return isFalseXmlBoolean(slide.show ?? slide["@_show"]);
+}
+
+async function applyHiddenSlidesToPptxBlob(blob: Blob, slides: Slide[]) {
+  const JSZip = await loadJsZip();
+  const zip = await JSZip.loadAsync(await blob.arrayBuffer());
+  await Promise.all(
+    slides.map(async (slide, index) => {
+      if (!slide.hidden) {
+        return;
+      }
+
+      const path = `ppt/slides/slide${index + 1}.xml`;
+      const xml = await zip.file(path)?.async("string");
+      if (xml) {
+        zip.file(path, pptxSlideXmlWithHiddenState(xml));
+      }
+    })
+  );
+
+  return zip.generateAsync({ type: "blob", mimeType: PPTX_MIME_TYPE });
+}
+
+function pptxSlideXmlWithHiddenState(xml: string) {
+  return xml.replace(/<p:sld\b([^>]*)>/, (_match, attributes: string) => {
+    const withoutShow = attributes.replace(/\sshow="[^"]*"/, "");
+    return `<p:sld${withoutShow} show="0">`;
+  });
+}
+
 function normalizeHexColor(value?: string) {
   const raw = value?.trim().replace(/^#/, "").toUpperCase() ?? "";
   return /^[0-9A-F]{6}$/.test(raw) ? raw : "";
@@ -490,17 +533,26 @@ function numberAttribute(record: Record<string, unknown>, name: string) {
   return Number.isFinite(value) ? value : undefined;
 }
 
+function isFalseXmlBoolean(value: unknown) {
+  const normalized = String(value ?? "").trim().toLowerCase();
+  return normalized === "0" || normalized === "false";
+}
+
 function emuToInches(value: number) {
   return Math.max(0, Math.round((value / emuPerInch) * 1000) / 1000);
 }
 
 async function loadZip(file: File): Promise<ZipArchive> {
-  const moduleName = "jszip";
-  const jsZipModule = (await import(moduleName)) as { default?: { loadAsync: (data: ArrayBuffer) => Promise<ZipArchive> } };
-  const jsZip = jsZipModule.default ?? (jsZipModule as unknown as { loadAsync: (data: ArrayBuffer) => Promise<ZipArchive> });
+  const jsZip = await loadJsZip();
   return jsZip.loadAsync(await readOfficeFileAsArrayBuffer(file));
 }
 
+async function loadJsZip(): Promise<ZipConstructor> {
+  const moduleName = "jszip";
+  const jsZipModule = (await import(moduleName)) as { default?: ZipConstructor } & ZipConstructor;
+  return jsZipModule.default ?? jsZipModule;
+}
+
 async function createXmlParser(): Promise<{ parse: (xml: string) => unknown }> {
   const moduleName = "fast-xml-parser";
   const parserModule = (await import(moduleName)) as { XMLParser: XmlParserConstructor };