fix: handle state change with identical or missing currentWidgetId

The pi exhibited an issue where a current widget could become stuck and
never continue to the next widget. It seems to be caused by clicking on
the current widget in the tab. Added some logging in case there are
other edge cases.

Author: cbarber

app/javascript/components/widget-controller.jsx

@@ -113,16 +113,27 @@ export class WidgetController extends React.Component {
   };
 
   nextWidget = () => {
-    this.setState(({ nextWidgetId }) =>
-      nextWidgetId
-        ? {
-            currentWidgetId: nextWidgetId,
-            nextWidgetId: null,
-            prevWidgetId: null,
-            transitionTime: null,
-          }
-        : {},
-    );
+    this.setState(state => {
+      const { nextWidgetId } = state;
+      if (!nextWidgetId) {
+        // eslint-disable-next-line
+        console.error(
+          `FATAL: nextWidgetId is undefined for nextWidget call. state: ${state}`,
+        );
+        return {
+          currentWidgetId: null,
+          nextWidgetId: null,
+          prevWidgetId: null,
+          transitionTime: null,
+        };
+      }
+      return {
+        currentWidgetId: nextWidgetId,
+        nextWidgetId: null,
+        prevWidgetId: null,
+        transitionTime: null,
+      };
+    });
   };
 
   prevWidget = () => {
@@ -139,12 +150,16 @@ export class WidgetController extends React.Component {
   };
 
   switchToPage = id => {
-    this.setState({
-      currentWidgetId: id,
-      nextWidgetId: null,
-      prevWidgetId: null,
-      transitionTime: null,
-    });
+    this.setState(({ currentWidgetId }) =>
+      currentWidgetId !== id
+        ? {
+            currentWidgetId: id,
+            nextWidgetId: null,
+            prevWidgetId: null,
+            transitionTime: null,
+          }
+        : {},
+    );
   };
 
   handleClicks = ({ target }) => {