Allow clearing filter query via `store.setFilterQuery(null)`

src/sidebar/store/modules/filters.ts

@@ -149,7 +149,7 @@ const reducers = {
     return { filters: updatedFilters };
   },
 
-  SET_FILTER_QUERY(state: State, action: { query: string }) {
+  SET_FILTER_QUERY(state: State, action: { query: string | null }) {
     return { query: action.query };
   },
 
@@ -217,9 +217,10 @@ function setFilter(filterName: FilterKey, filterOption: FilterOption) {
 }
 
 /**
- * Set the query used to filter displayed annotations.
+ * Set the query used to filter displayed annotations or `null` to clear the
+ * filter.
  */
-function setFilterQuery(query: string) {
+function setFilterQuery(query: string | null) {
   return makeAction(reducers, 'SET_FILTER_QUERY', { query });
 }
 

src/sidebar/store/modules/test/filters-test.js

@@ -138,10 +138,12 @@ describe('sidebar/store/modules/filters', () => {
     });
 
     describe('setFilterQuery', () => {
-      it('sets the filter query', () => {
-        store.setFilterQuery('a-query');
-        assert.equal(getFiltersState().query, 'a-query');
-        assert.equal(store.filterQuery(), 'a-query');
+      ['a-query', '', null].forEach(query => {
+        it('sets the filter query', () => {
+          store.setFilterQuery(query);
+          assert.equal(getFiltersState().query, query);
+          assert.equal(store.filterQuery(), query);
+        });
       });
     });