diff -u b/core/tests/Drupal/Tests/Core/TypedData/MapDataNormalizeTest.php b/core/tests/Drupal/Tests/Core/TypedData/MapDataNormalizeTest.php
--- b/core/tests/Drupal/Tests/Core/TypedData/MapDataNormalizeTest.php
+++ b/core/tests/Drupal/Tests/Core/TypedData/MapDataNormalizeTest.php
@@ -65,8 +65,6 @@
 
   /**
    * Builds some example type data object with no properties.
-   *
-   * @return \Drupal\Core\TypedData\TypedDataInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected function buildExampleTypedData() {
     $tree = [
@@ -84,8 +82,6 @@
 
   /**
    * Builds some example type data object with properties.
-   *
-   * @return \Drupal\Core\TypedData\TypedDataInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected function buildExampleTypedDataWithProperties() {
     $tree = [
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Core\TypedData\Plugin\DataType;
 
+use Drupal\Core\TypedData\DataDefinition;
 use Drupal\Core\TypedData\TypedData;
 use Drupal\Core\TypedData\ComplexDataInterface;
 
@@ -113,7 +114,8 @@ public function get($property_name) {
         $value = $this->values[$property_name];
       }
       // If the property is unknown, this will throw an exception.
-      $this->properties[$property_name] = $this->getTypedDataManager()->getPropertyInstance($this, $property_name, $value);
+      $this->properties[$property_name] = $this->getTypedDataManager()
+        ->getPropertyInstance($this, $property_name, $value);
     }
     return $this->properties[$property_name];
   }
@@ -155,11 +157,29 @@ protected function writePropertyValue($property_name, $value) {
    */
   public function getProperties($include_computed = FALSE) {
     $properties = [];
-    foreach ($this->definition->getPropertyDefinitions() as $name => $definition) {
-      if ($include_computed || !$definition->isComputed()) {
-        $properties[$name] = $this->get($name);
+    $PropertyDefinitions = $this->definition->getPropertyDefinitions();
+    if (!empty($PropertyDefinitions)) {
+      foreach ($PropertyDefinitions as $name => $definition) {
+        if ($include_computed || !$definition->isComputed()) {
+          $properties[$name] = $this->get($name);
+        }
+      }
+    }
+    //If module creator send an array to map dataType and don't setPropertyDefinition,
+    //Auto creating the PropertyDefinition so that it can be normalized
+    elseif (get_class($this->getDataDefinition()) == 'Drupal\Core\TypedData\MapDataDefinition') {
+      $values = $this->values;
+      if (is_array($values)) {
+        foreach ($values as $key => $value) {
+          $properties[$key] = \Drupal::typedDataManager()->create(
+            DataDefinition::create('any'),
+            $value,
+            $key
+          );
+        };
       }
     }
+
     return $properties;
   }