From 9f59a73049655608cd0cb05be7db5231ece27aef Mon Sep 17 00:00:00 2001
From: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Date: Tue, 2 Feb 2021 13:27:37 +0100
Subject: [PATCH] Fix wrong acces to slide options

If the slide options in the frontmatter are empty
or not present, then slideOptions object in the
parsed JSON is undefined. This triggers an
exception when the sanitized slide options object
is built.

Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
---
 public/js/slide.js | 99 +++++++++++++++++++++++-----------------------
 1 file changed, 50 insertions(+), 49 deletions(-)

diff --git a/public/js/slide.js b/public/js/slide.js
index e0e831cac..b8374cbbe 100644
--- a/public/js/slide.js
+++ b/public/js/slide.js
@@ -72,56 +72,57 @@ const defaultOptions = {
 
 // options from yaml meta
 const meta = JSON.parse($('#meta').text())
+const metaSlideOptions = !!meta && !!meta.slideOptions ? meta.slideOptions : {}
 var options = {
-  autoPlayMedia: meta.slideOptions.autoPlayMedia,
-  autoSlide: meta.slideOptions.autoSlide,
-  autoSlideStoppable: meta.slideOptions.autoSlideStoppable,
-  backgroundTransition: meta.slideOptions.backgroundTransition,
-  center: meta.slideOptions.center,
-  controls: meta.slideOptions.controls,
-  controlsBackArrows: meta.slideOptions.controlsBackArrows,
-  controlsLayout: meta.slideOptions.controlsLayout,
-  controlsTutorial: meta.slideOptions.controlsTutorial,
-  defaultTiming: meta.slideOptions.defaultTiming,
-  display: meta.slideOptions.display,
-  embedded: meta.slideOptions.embedded,
-  fragmentInURL: meta.slideOptions.fragmentInURL,
-  fragments: meta.slideOptions.fragments,
-  hash: meta.slideOptions.hash,
-  height: meta.slideOptions.height,
-  help: meta.slideOptions.help,
-  hideAddressBar: meta.slideOptions.hideAddressBar,
-  hideCursorTime: meta.slideOptions.hideCursorTime,
-  hideInactiveCursor: meta.slideOptions.hideInactiveCursor,
-  history: meta.slideOptions.history,
-  keyboard: meta.slideOptions.keyboard,
-  loop: meta.slideOptions.loop,
-  margin: meta.slideOptions.margin,
-  maxScale: meta.slideOptions.maxScale,
-  minScale: meta.slideOptions.minScale,
-  minimumTimePerSlide: meta.slideOptions.minimumTimePerSlide,
-  mobileViewDistance: meta.slideOptions.mobileViewDistance,
-  mouseWheel: meta.slideOptions.mouseWheel,
-  navigationMode: meta.slideOptions.navigationMode,
-  overview: meta.slideOptions.overview,
-  parallaxBackgroundHorizontal: meta.slideOptions.parallaxBackgroundHorizontal,
-  parallaxBackgroundImage: meta.slideOptions.parallaxBackgroundImage,
-  parallaxBackgroundSize: meta.slideOptions.parallaxBackgroundSize,
-  parallaxBackgroundVertical: meta.slideOptions.parallaxBackgroundVertical,
-  preloadIframes: meta.slideOptions.preloadIframes,
-  previewLinks: meta.slideOptions.previewLinks,
-  progress: meta.slideOptions.progress,
-  rtl: meta.slideOptions.rtl,
-  showNotes: meta.slideOptions.showNotes,
-  shuffle: meta.slideOptions.shuffle,
-  slideNumber: meta.slideOptions.slideNumber,
-  theme: meta.slideOptions.theme,
-  totalTime: meta.slideOptions.totalTime,
-  touch: meta.slideOptions.touch,
-  transition: meta.slideOptions.transition,
-  transitionSpeed: meta.slideOptions.transitionSpeed,
-  viewDistance: meta.slideOptions.viewDistance,
-  width: meta.slideOptions.width
+  autoPlayMedia: metaSlideOptions.autoPlayMedia,
+  autoSlide: metaSlideOptions.autoSlide,
+  autoSlideStoppable: metaSlideOptions.autoSlideStoppable,
+  backgroundTransition: metaSlideOptions.backgroundTransition,
+  center: metaSlideOptions.center,
+  controls: metaSlideOptions.controls,
+  controlsBackArrows: metaSlideOptions.controlsBackArrows,
+  controlsLayout: metaSlideOptions.controlsLayout,
+  controlsTutorial: metaSlideOptions.controlsTutorial,
+  defaultTiming: metaSlideOptions.defaultTiming,
+  display: metaSlideOptions.display,
+  embedded: metaSlideOptions.embedded,
+  fragmentInURL: metaSlideOptions.fragmentInURL,
+  fragments: metaSlideOptions.fragments,
+  hash: metaSlideOptions.hash,
+  height: metaSlideOptions.height,
+  help: metaSlideOptions.help,
+  hideAddressBar: metaSlideOptions.hideAddressBar,
+  hideCursorTime: metaSlideOptions.hideCursorTime,
+  hideInactiveCursor: metaSlideOptions.hideInactiveCursor,
+  history: metaSlideOptions.history,
+  keyboard: metaSlideOptions.keyboard,
+  loop: metaSlideOptions.loop,
+  margin: metaSlideOptions.margin,
+  maxScale: metaSlideOptions.maxScale,
+  minScale: metaSlideOptions.minScale,
+  minimumTimePerSlide: metaSlideOptions.minimumTimePerSlide,
+  mobileViewDistance: metaSlideOptions.mobileViewDistance,
+  mouseWheel: metaSlideOptions.mouseWheel,
+  navigationMode: metaSlideOptions.navigationMode,
+  overview: metaSlideOptions.overview,
+  parallaxBackgroundHorizontal: metaSlideOptions.parallaxBackgroundHorizontal,
+  parallaxBackgroundImage: metaSlideOptions.parallaxBackgroundImage,
+  parallaxBackgroundSize: metaSlideOptions.parallaxBackgroundSize,
+  parallaxBackgroundVertical: metaSlideOptions.parallaxBackgroundVertical,
+  preloadIframes: metaSlideOptions.preloadIframes,
+  previewLinks: metaSlideOptions.previewLinks,
+  progress: metaSlideOptions.progress,
+  rtl: metaSlideOptions.rtl,
+  showNotes: metaSlideOptions.showNotes,
+  shuffle: metaSlideOptions.shuffle,
+  slideNumber: metaSlideOptions.slideNumber,
+  theme: metaSlideOptions.theme,
+  totalTime: metaSlideOptions.totalTime,
+  touch: metaSlideOptions.touch,
+  transition: metaSlideOptions.transition,
+  transitionSpeed: metaSlideOptions.transitionSpeed,
+  viewDistance: metaSlideOptions.viewDistance,
+  width: metaSlideOptions.width
 } || {}
 
 for (const key in options) {