fix

index.js

@@ -78,6 +78,14 @@ function is_nil (obj) {
       || (typeof obj === 'number' && isNaN (obj));
 }
 
+function to_search_string (element, field) {
+  return Array.isArray (field)
+    ? field.map ((f) => element[f])
+      .filter ((v) => typeof v !== 'undefined')
+      .join (' ')
+    : element[field];
+}
+
 /**
  * filter nested objects
  *
@@ -93,14 +101,7 @@ function recursive_filter (input, filters, children_key = 'children') {
     data[i] = e;
     let match = true;
     for (const filter of filters) {
-      const is_multi_filter
+      const search_str = to_search_string(e, filter.field);
-      = Array.isArray (filter.fields);
-
-      const search_str = is_multi_filter
-        ? filter.fields.map ((f) => e[f])
-          .filter ((v) => typeof v !== 'undefined')
-          .join (' ')
-        : e[filter.field];
 
       if (!filter.filter.test (search_str)) {
         match = false;