From 6410ed15aa5ce2bdfc1f7f02c818a562ec8a1fc4 Mon Sep 17 00:00:00 2001
From: Hakim El Hattab <hakim.elhattab@gmail.com>
Date: Thu, 14 Mar 2019 14:52:59 +0100
Subject: [PATCH] support for plugins where the init method doesn't return a
 Promise

---
 js/reveal.js                  | 29 +++++++++++++++++------------
 plugin/highlight/highlight.js |  2 --
 plugin/math/math.js           |  2 --
 plugin/notes/notes.js         |  2 --
 plugin/zoom-js/zoom.js        |  2 --
 5 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/js/reveal.js b/js/reveal.js
index 1ef10aab..51b1ed03 100644
--- a/js/reveal.js
+++ b/js/reveal.js
@@ -539,29 +539,34 @@
 
 		var pluginsToInitialize = Object.keys( plugins ).length;
 
+		var afterPlugInitialized = function() {
+			if( --pluginsToInitialize === 0 ) {
+				loadAsyncDependencies();
+			}
+		};
+
 		for( var i in plugins ) {
 
 			var plugin = plugins[i];
 
-			// If the plugin has an 'init' method, initialize and
-			// wait for the callback
+			// If the plugin has an 'init' method, invoke it
 			if( typeof plugin.init === 'function' ) {
-				plugin.init().then( function() {
-					if( --pluginsToInitialize === 0 ) {
-						loadAsyncDependencies();
-					}
-				} );
+				var callback = plugin.init();
+
+				// If the plugin returned a Promise, wait for it
+				if( callback && typeof callback.then === 'function' ) {
+					callback.then( afterPlugInitialized );
+				}
+				else {
+					afterPlugInitialized();
+				}
 			}
 			else {
-				pluginsToInitialize -= 1;
+				afterPlugInitialized();
 			}
 
 		}
 
-		if( pluginsToInitialize === 0 ) {
-			loadAsyncDependencies();
-		}
-
 	}
 
 	/**
diff --git a/plugin/highlight/highlight.js b/plugin/highlight/highlight.js
index 6d6910b9..b3599e88 100644
--- a/plugin/highlight/highlight.js
+++ b/plugin/highlight/highlight.js
@@ -97,8 +97,6 @@ c:[{cN:"comment",b:/\(\*/,e:/\*\)/},e.ASM,e.QSM,e.CNM,{b:/\{/,e:/\}/,i:/:/}]}});
 				}
 			} );
 
-			return Promise.resolve();
-
 		},
 
 		/**
diff --git a/plugin/math/math.js b/plugin/math/math.js
index b78d1209..d76c9dda 100755
--- a/plugin/math/math.js
+++ b/plugin/math/math.js
@@ -84,8 +84,6 @@ var RevealMath = window.RevealMath || (function(){
 
 			} );
 
-			return Promise.resolve();
-
 		}
 	}
 
diff --git a/plugin/notes/notes.js b/plugin/notes/notes.js
index 54dcf314..3d5eac4b 100644
--- a/plugin/notes/notes.js
+++ b/plugin/notes/notes.js
@@ -168,8 +168,6 @@ var RevealNotes = (function() {
 
 			}
 
-			return Promise.resolve();
-
 		},
 
 		open: openNotes
diff --git a/plugin/zoom-js/zoom.js b/plugin/zoom-js/zoom.js
index 031514d9..92c3ba5b 100644
--- a/plugin/zoom-js/zoom.js
+++ b/plugin/zoom-js/zoom.js
@@ -22,8 +22,6 @@ var RevealZoom = (function(){
 				}
 			} );
 
-			return Promise.resolve();
-
 		}
 	}