Improve promise handling

view-train.js

@@ -316,9 +316,11 @@ function refresh() {
 		}
 		return response.json()
 	}).then(function (response) {
+		if (!response) {
+			return
+		}
 		trainData = response
 		onTrainData(response)
-	}).then(function () {
 		reschedule()
 	}).catch(function (e) {
 		// Check in 1 second if network error