fix(map): preserve empty facet selection

apps/catalog/src/mapPresentationProfile.ts

@@ -106,8 +106,9 @@ export function mapPresentationBindingIsAll(bindingId: string, filters: MapPrese
 
 /**
  * Apply one interactive facet-chip transition without collapsing the storage
- * contract. A missing field means unconstrained, while an explicitly persisted
- * empty array remains available to represent an intentional match-nothing view.
+ * contract. A missing field means that facet is not part of the current union,
+ * while one explicitly empty field represents the intentional match-nothing
+ * view after the final selected chip is switched off.
  */
 export function toggleMapPresentationFacetSelection(
   facets: Record<string, string[]>,
@@ -116,14 +117,30 @@ export function toggleMapPresentationFacetSelection(
 ) {
   const selected = facets[field];
   if (!selected?.includes(value)) {
-    return { ...facets, [field]: [...(selected ?? []), value] };
+    // A saved empty view can contain one or more empty facet arrays. They are
+    // a global zero-match sentinel, not active constraints, so selecting the
+    // first chip must replace them instead of leaving a hidden empty array that
+    // would continue to suppress every fact.
+    const activeFacets = Object.fromEntries(
+      Object.entries(facets).filter(([, values]) => values.length > 0),
+    );
+    return { ...activeFacets, [field]: [...(activeFacets[field] ?? []), value] };
   }
 
   const nextSelected = selected.filter((item) => item !== value);
   if (nextSelected.length > 0) return { ...facets, [field]: nextSelected };
 
-  const { [field]: _removed, ...unconstrained } = facets;
-  return unconstrained;
+  const { [field]: _removed, ...remaining } = facets;
+  const activeFacets = Object.fromEntries(
+    Object.entries(remaining).filter(([, values]) => values.length > 0),
+  );
+  if (Object.keys(activeFacets).length > 0) return activeFacets;
+
+  // Never collapse the last interactive deselection to `{}`: the renderer
+  // correctly interprets `{}` as unconstrained/all. Retain an explicit empty
+  // facet so the zero-selection state remains zero matches through any toggle
+  // cycle and through a later Application Save.
+  return { [field]: [] };
 }
 
 export function mapPresentationProfileForFact(
@@ -192,9 +209,8 @@ export function mapFactMatchesFilters(
     return [{ facet, selected }];
   });
 
-  // Persisted empty arrays are an explicit match-nothing state. Interactive
-  // deselection removes the field instead, so this branch is only reached for
-  // a deliberately saved empty view.
+  // Persisted empty arrays and the final interactive deselection are an
+  // explicit match-nothing state.
   if (selectedFacets.some(({ selected }) => selected.length === 0)) return false;
   if (selectedFacets.length === 0) return true;
 

scripts/map-presentation-filters.test.mjs

@@ -49,13 +49,53 @@ test("deselecting the last chip remains empty and never normalizes to all", () =
   assert.equal(mapFactMatchesFilters(onlineMoving, profile, filters, "fleet"), false);
 });
 
-test("interactive deselect of the last chip removes the facet constraint", () => {
+test("interactive deselect of the last chip preserves the zero-match state", () => {
   const selected = toggleMapPresentationFacetSelection({}, "signal_state", "active");
   assert.deepEqual(selected, { signal_state: ["active"] });
 
-  const unconstrained = toggleMapPresentationFacetSelection(selected, "signal_state", "active");
-  assert.deepEqual(unconstrained, {});
-  assert.equal(mapPresentationBindingIsAll("fleet", { fleet: { visible: true, facets: unconstrained } }), true);
+  const empty = toggleMapPresentationFacetSelection(selected, "signal_state", "active");
+  const filters = { fleet: { visible: true, facets: empty } };
+  assert.deepEqual(empty, { signal_state: [] });
+  assert.equal(mapPresentationBindingIsAll("fleet", filters), false);
+  assert.equal(mapFactMatchesFilters(onlineMoving, profile, filters, "fleet"), false);
+});
+
+test("the first chip selected after a saved empty view removes every empty sentinel", () => {
+  const selected = toggleMapPresentationFacetSelection({
+    signal_state: [],
+    movement_state: [],
+  }, "signal_state", "active");
+
+  assert.deepEqual(selected, { signal_state: ["active"] });
+  assert.equal(mapFactMatchesFilters(onlineMoving, profile, {
+    fleet: { visible: true, facets: selected },
+  }, "fleet"), true);
+});
+
+test("a complete interactive toggle cycle returns to zero matches instead of all", () => {
+  let facets = { signal_state: [], movement_state: [] };
+  const toggle = (field, value) => {
+    facets = toggleMapPresentationFacetSelection(facets, field, value);
+  };
+
+  toggle("signal_state", "active");
+  toggle("signal_state", "inactive");
+  toggle("movement_state", "moving");
+  toggle("movement_state", "stopped");
+  assert.deepEqual(facets, {
+    signal_state: ["active", "inactive"],
+    movement_state: ["moving", "stopped"],
+  });
+
+  toggle("signal_state", "active");
+  toggle("signal_state", "inactive");
+  toggle("movement_state", "moving");
+  toggle("movement_state", "stopped");
+
+  const filters = { fleet: { visible: true, facets } };
+  assert.deepEqual(facets, { movement_state: [] });
+  assert.equal(mapPresentationBindingIsAll("fleet", filters), false);
+  assert.equal(mapFactMatchesFilters(onlineMoving, profile, filters, "fleet"), false);
 });
 
 test("interactive deselect preserves other values and facet constraints", () => {