From c9a5a943b6ac384f1f3a1247ca3804ab1cb8f376 Mon Sep 17 00:00:00 2001
From: Boris Goldowsky <bgoldowsky@concord.org>
Date: Thu, 19 Sep 2024 16:23:02 -0400
Subject: [PATCH] Don't do init steps on all dataset changes. Take more care
 with undefined vs. falsy

---
 src/plugins/data-card/data-card-content.ts | 19 +++++++++++--------
 src/plugins/data-card/data-card-tile.tsx   |  5 +++--
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/plugins/data-card/data-card-content.ts b/src/plugins/data-card/data-card-content.ts
index bdc1a3891..8e3054335 100644
--- a/src/plugins/data-card/data-card-content.ts
+++ b/src/plugins/data-card/data-card-content.ts
@@ -135,7 +135,7 @@ export const DataCardContentModel = TileContentModel
   }))
   .views(self => ({
     get caseId() {
-      return self.caseIndex ? self.dataSet.caseIDFromIndex(self.caseIndex) : undefined;
+      return self.caseIndex !== undefined ? self.dataSet.caseIDFromIndex(self.caseIndex) : undefined;
     }
   }))
   .views(self => ({
@@ -260,13 +260,16 @@ export const DataCardContentModel = TileContentModel
     updateAfterSharedModelChanges(sharedModel?: SharedModelType) {
       const dataSet = self.dataSet;
       if (!dataSet) return;
-      // Select the card of the first selected case
-      const selectedCaseId = dataSet.firstSelectedCaseId
-        ? dataSet.firstSelectedCaseId : dataSet.firstSelectedCell?.caseId;
-      if (selectedCaseId && dataSet.caseIndexFromID(selectedCaseId) !== self.caseIndex) {
-        self.setCaseIndex(dataSet.caseIndexFromID(selectedCaseId));
-      } else if (self.caseIndex === undefined) {
-        self.setCaseIndex(0);
+      // At initialization, caseIndex will be undefined.
+      // Set it to the first selected case, or the first card if there's no selection.
+      if (self.caseIndex === undefined) {
+        const selectedCaseId = dataSet.firstSelectedCaseId !== undefined
+          ? dataSet.firstSelectedCaseId : dataSet.firstSelectedCell?.caseId;
+        if (selectedCaseId !== undefined) {
+          self.setCaseIndex(dataSet.caseIndexFromID(selectedCaseId));
+        } else {
+          self.setCaseIndex(0);
+        }
       } else if (self.caseIndex >= self.totalCases && self.totalCases > 0) {
         // Make sure case index is in range if number of cases has changed
         self.setCaseIndex(self.totalCases - 1);
diff --git a/src/plugins/data-card/data-card-tile.tsx b/src/plugins/data-card/data-card-tile.tsx
index 12f058307..9d63c3cc3 100644
--- a/src/plugins/data-card/data-card-tile.tsx
+++ b/src/plugins/data-card/data-card-tile.tsx
@@ -50,10 +50,11 @@ export const DataCardToolComponent: React.FC<ITileProps> = observer(function Dat
   const cardOf = `Card ${content.caseIndexNumber + 1 } of `;
 
   // When a highlighted case or cell is set, show it
-  const selectedCaseId = dataSet.firstSelectedCaseId ? dataSet.firstSelectedCaseId : dataSet.firstSelectedCell?.caseId;
+  const selectedCaseId = dataSet.firstSelectedCaseId !== undefined
+    ? dataSet.firstSelectedCaseId : dataSet.firstSelectedCell?.caseId;
   useEffect(() => {
     if (content.caseIndex === undefined) return;
-    if (selectedCaseId && dataSet.caseIndexFromID(selectedCaseId) !== content.caseIndex) {
+    if (selectedCaseId !== undefined && dataSet.caseIndexFromID(selectedCaseId) !== content.caseIndex) {
       content.setCaseIndex(dataSet.caseIndexFromID(selectedCaseId));
     }
   }, [content, dataSet, selectedCaseId]);