Merge pull request #455 from marp-team/inconsistent-transition-in-backward-navigation-via-presenter

Fix inconsistent transition by backward navigation via presenter view

Author: yhatt

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Fixed
 
+- [Experimental transition] Fix inconsistent transition by backward navigation via presenter view ([#452](https://github.com/marp-team/marp-cli/issues/452), [#455](https://github.com/marp-team/marp-cli/pull/455))
 - Preview mode has unexpected message in the information bar "You are using an unsupported command-line flag" ([#453](https://github.com/marp-team/marp-cli/issues/453), [#454](https://github.com/marp-team/marp-cli/pull/454))
 
 ## v2.0.0 - 2022-05-24

src/templates/bespoke/transition.ts

@@ -115,6 +115,10 @@ const bespokeTransition = (deck) => {
         return false
       }
 
+      // Check condition
+      // (The conditional function may modify event object so should be called at first of checks)
+      if (!cond(e)) return true
+
       // Check transition
       const current = deck.slides[deck.slide()]
       const isBack = () => e.back ?? back
@@ -124,9 +128,6 @@ const bespokeTransition = (deck) => {
       )
       if (!section) return true
 
-      // Check condition
-      if (!cond(e)) return true
-
       // Parse settings
       const transitionData = parseTransitionData(
         section.getAttribute(transitionDataTarget) ?? undefined