Hierarchical facet: allow selecting parents with 0 hits

src/client/components/facet_bar/HierarchicalFacet.js

@@ -188,8 +188,11 @@ class HierarchicalFacet extends Component {
               className={this.props.classes.checkbox}
               checked={isSelected}
               disabled={
-                // prevent selecting values with 0 hits (which may appear based on earlier selections):
-                (treeObj.node.instanceCount == 0 && treeObj.node.selected === 'false')
+                /* non-hierarchical facet:
+                prevent selecting values with 0 hits (which may appear based on earlier selections): */
+                (this.props.facet.type !== 'hierarchical'
+                && treeObj.node.instanceCount == 0
+                && treeObj.node.selected === 'false')
                 // prevent selecting unknown value:
                 || treeObj.node.prefLabel == 'Unknown'
                 // prevent selecting when another facet is still updating:

src/client/reducers/manuscriptsFacets.js

@@ -50,7 +50,8 @@ export const INITIAL_STATE = {
       containerClass: 'ten',
       filterType: 'uriFilter',
       uriFilter: null,
-      spatialFilter: null
+      spatialFilter: null,
+      type: 'hierarchical',
     },
     // productionDate: {
     //   id: 'productionDate',