automatically select correct term

src/lib/DatasetViewer.svelte

@@ -28,6 +28,10 @@
   let selectedTerm1 = $state<string | null>(null);
   let selectedTerm2 = $state<string | null>(null);
 
+  // Track previous selected terms for detecting user-initiated changes (loop prevention)
+  let prevSelectedTerm1 = $state<string | null>(null);
+  let prevSelectedTerm2 = $state<string | null>(null);
+
   // UI state
   let loading = $state(false);
   let error = $state("");
@@ -63,6 +67,8 @@
     equivalencyScores = [];
     selectedTerm1 = null;
     selectedTerm2 = null;
+    prevSelectedTerm1 = null;
+    prevSelectedTerm2 = null;
     hasLoaded = false;
 
     try {
@@ -92,8 +98,14 @@
       hasLoaded = true;
 
       // Auto-select first term if available
-      if (data1.length > 0) selectedTerm1 = data1[0].term;
-      if (data2.length > 0) selectedTerm2 = data2[0].term;
+      if (data1.length > 0) {
+        selectedTerm1 = data1[0].term;
+        prevSelectedTerm1 = data1[0].term;
+      }
+      if (data2.length > 0) {
+        selectedTerm2 = data2[0].term;
+        prevSelectedTerm2 = data2[0].term;
+      }
     } catch (e) {
       error = e instanceof Error ? e.message : "Failed to load jurisdictions";
       console.error("Jurisdiction loading error:", e);
@@ -128,6 +140,49 @@
     return translationMap.get(normalized) || null;
   }
 
+  // Find a term in a data array by its normalized form
+  function findTermInData(
+    normalizedTarget: string,
+    data: TermDefinition[]
+  ): string | null {
+    const found = data.find(
+      (item) => normalizeTermForComparison(item.term) === normalizedTarget
+    );
+    return found?.term || null;
+  }
+
+  // Auto-select direct translation when selectedTerm1 changes (user-initiated)
+  $effect(() => {
+    const current = selectedTerm1;
+    if (current && current !== prevSelectedTerm1 && data2.length > 0) {
+      const translation = getDirectTranslation(current);
+      if (translation) {
+        const matchingTerm = findTermInData(translation, data2);
+        if (matchingTerm && matchingTerm !== selectedTerm2) {
+          selectedTerm2 = matchingTerm;
+          prevSelectedTerm2 = matchingTerm;
+        }
+      }
+      prevSelectedTerm1 = current;
+    }
+  });
+
+  // Auto-select direct translation when selectedTerm2 changes (user-initiated)
+  $effect(() => {
+    const current = selectedTerm2;
+    if (current && current !== prevSelectedTerm2 && data1.length > 0) {
+      const translation = getDirectTranslation(current);
+      if (translation) {
+        const matchingTerm = findTermInData(translation, data1);
+        if (matchingTerm && matchingTerm !== selectedTerm1) {
+          selectedTerm1 = matchingTerm;
+          prevSelectedTerm1 = matchingTerm;
+        }
+      }
+      prevSelectedTerm2 = current;
+    }
+  });
+
   // Check if a term should be highlighted based on the selected term in the other jurisdiction
   function shouldHighlightTerm(
     term: string,