diff --git a/src/components/datatable/DataTable.vue b/src/components/datatable/DataTable.vue
index a5cb224c05..3d3fd8213c 100644
--- a/src/components/datatable/DataTable.vue
+++ b/src/components/datatable/DataTable.vue
@@ -232,7 +232,7 @@ export default {
         },
         filterLocale: {
             type: String,
-            default: null
+            default: undefined
         },
         selection: {
             type: [Array,Object],
diff --git a/src/components/tree/Tree.vue b/src/components/tree/Tree.vue
index 7acf871c8b..010d756cb4 100644
--- a/src/components/tree/Tree.vue
+++ b/src/components/tree/Tree.vue
@@ -71,7 +71,7 @@ export default {
         },
         filterLocale: {
             type: String,
-            default: null
+            default: undefined
         }
     },
     data() {
@@ -412,4 +412,4 @@ export default {
 .p-tree .p-tree-loading-content .p-tree-loading-icon {
     font-size: 2em;
 }
-</style>
\ No newline at end of file
+</style>
diff --git a/src/components/treetable/TreeTable.vue b/src/components/treetable/TreeTable.vue
index 555797097f..d5473bcd4e 100644
--- a/src/components/treetable/TreeTable.vue
+++ b/src/components/treetable/TreeTable.vue
@@ -202,7 +202,7 @@ export default {
         },
         filterLocale: {
             type: String,
-            default: null
+            default: undefined
         },
         resizableColumns: {
             type: Boolean,
@@ -1110,4 +1110,4 @@ export default {
 .p-treetable .p-treetable-loading-icon {
     font-size: 2em;
 }
-</style>
\ No newline at end of file
+</style>