improved slide preview for notebooks (return last slide)

Author: jjallaire

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## 1.51.0 (Unreleased)
 
 - Always render on save for notebooks (as they don't execute by default)
+- Improved slide preview for notebooks (return last slide)
 
 ## 1.50.0 (Release on 19 October 2022)
 

assets/www/preview/index.js

@@ -23,7 +23,7 @@ const reloadButton = header.querySelector(".reload-button");
 const openExternalButton = header.querySelector(".open-external-button");
 const kQuartoPreviewReqId = "quartoPreviewReqId";
 const kQuartoPreviewThemeCategory = "quartoPreviewThemeCategory";
-let slideIndex = 0;
+let slideIndex = undefined;
 
 const updateAddressBar = (href) => {
   const url = new URL(href);
@@ -76,18 +76,20 @@ window.addEventListener("message", (e) => {
       break;
     }
     case "setSlideIndex": {
-      slideIndex = e.data.index || 0;
+      slideIndex = e.data.index;
       break;
     }
     case "reveal-init": {
       // set the slide index
       const slides = e.data.data.slides;
-      const slide = slides[slideIndex];
-      if (slide) {
-        e.source.postMessage(
-          { message: "reveal-slide", data: slide },
-          e.origin
-        );
+      if (slideIndex !== undefined) {
+        const slide = slides[slideIndex];
+        if (slide) {
+          e.source.postMessage(
+            { message: "reveal-slide", data: slide },
+            e.origin
+          );
+        }
       }
 
       // let reveal know we are ready for additional messages

src/providers/preview/preview-webview.ts

@@ -22,7 +22,7 @@ export class QuartoPreviewWebviewManager extends QuartoWebviewManager<
       this.activeView_.clear();
     }
   }
-  public setSlideIndex(slideIndex: number) {
+  public setSlideIndex(slideIndex?: number) {
     if (this.activeView_) {
       this.activeView_.setSlideIndex(slideIndex);
     }
@@ -102,7 +102,7 @@ export class QuartoPreviewWebview extends QuartoWebview<string> {
     });
   }
 
-  public setSlideIndex(slideIndex: number) {
+  public setSlideIndex(slideIndex?: number) {
     this._webviewPanel.webview.postMessage({
       type: "setSlideIndex",
       index: slideIndex,

src/providers/preview/preview.ts

@@ -154,6 +154,8 @@ export async function previewDoc(
       previewManager.setSlideIndex(
         await revealSlideIndex(editor.selection.active, editor.document, engine)
       );
+    } else {
+      previewManager.setSlideIndex(undefined);
     }
   }
   //  set onShow if provided
@@ -263,7 +265,7 @@ class PreviewManager {
     }
   }
 
-  public setSlideIndex(slideIndex: number) {
+  public setSlideIndex(slideIndex?: number) {
     this.webviewManager_.setSlideIndex(slideIndex);
   }