diff --git a/mixins/generator/generator_param_mixin.js b/mixins/generator/generator_param_mixin.js
index 76901c9..f104821 100644
--- a/mixins/generator/generator_param_mixin.js
+++ b/mixins/generator/generator_param_mixin.js
@@ -17,7 +17,7 @@ export default {
           const namespace = entry[0]
 
           const subObject = this.modifiedParams[namespace]
-          if (subObject && typeof subObject.valueOf() === 'string') {
+          if (subObject && Array.isArray(subObject)) {
             const out = {}
             out[namespace] = subObject
             return out