handle cases when plugin data is not loaded yet

CHANGELOG

@@ -11,6 +11,8 @@ minerva (14.0.11) stable; urgency=medium
     CellDesigner file minerva (#1203)
   * Bug fix: author list inproperly presented author data when some fields were
     missing (#1201)
+  * Bug fix: refreshing minerva page with more than one plugin opened might
+    led to an error due to race condition (#1197)
 
  -- Piotr Gawron <piotr.gawron@uni.lu>  Mon, 30 Mar 2020 10:00:00 +0200
 

frontend-js/src/main/js/plugin/Plugin.js

@@ -80,7 +80,7 @@ Plugin.prototype.setLoadedPluginData = function (loadedPluginData) {
 
 /**
  *
- * @returns {UserPluginObject}
+ * @returns {?null|UserPluginObject}
  */
 Plugin.prototype.getLoadedPluginData = function () {
   return this._loadedPluginData;
@@ -189,11 +189,15 @@ Plugin.prototype.load = function () {
 Plugin.prototype.getMinWidth = function () {
   var value;
   var data = this.getLoadedPluginData();
-  if (data.minWidth !== undefined) {
-    if (typeof data.minWidth === "function") {
-      value = parseInt(data.minWidth());
-    } else {
-      value = parseInt(data.minWidth);
+  if (data === undefined || data === null) { //this can happen when plugin is added to list of plugins but data was not loaded yet
+    logger.warn("[" + this.getName() + "] Plugin data not available. ");
+  } else {
+    if (data.minWidth !== undefined) {
+      if (typeof data.minWidth === "function") {
+        value = parseInt(data.minWidth());
+      } else {
+        value = parseInt(data.minWidth);
+      }
     }
   }
   return value;