From 1c9ca30d6f1610a36c5e7754b87e3f585227e0fe Mon Sep 17 00:00:00 2001
From: Josh de Leeuw <josh.deleeuw@gmail.com>
Date: Mon, 28 Jun 2021 13:16:58 -0400
Subject: [PATCH] return 0 when no gazeData (possibly fixes #1724)

---
 plugins/jspsych-webgazer-validate.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/plugins/jspsych-webgazer-validate.js b/plugins/jspsych-webgazer-validate.js
index c014ae05..e25224a2 100644
--- a/plugins/jspsych-webgazer-validate.js
+++ b/plugins/jspsych-webgazer-validate.js
@@ -241,6 +241,9 @@
 
     function calculateSampleRate(gazeData){
       var mean_diff = [];
+      if(gazeData.length == 0){
+        return 0;
+      }
       for(var i=0; i<gazeData.length; i++){
         if(gazeData[i].length > 1){
           var t_diff = [];
@@ -255,7 +258,6 @@
       } else {
         return null;
       }
-      
     }
 
     function validation_done(){