diff --git a/common/src/main/kotlin/de/sipgate/federmappe/common/ErrorHandler.kt b/common/src/main/kotlin/de/sipgate/federmappe/common/ErrorHandler.kt
new file mode 100644
index 0000000..0048a79
--- /dev/null
+++ b/common/src/main/kotlin/de/sipgate/federmappe/common/ErrorHandler.kt
@@ -0,0 +1,3 @@
+package de.sipgate.federmappe.common
+
+typealias ErrorHandler<T> = (Throwable) -> T?
diff --git a/firestore/src/main/java/de/sipgate/federmappe/firestore/DocumentSnapshotExt.kt b/firestore/src/main/java/de/sipgate/federmappe/firestore/DocumentSnapshotExt.kt
index 97a851d..8ebc286 100644
--- a/firestore/src/main/java/de/sipgate/federmappe/firestore/DocumentSnapshotExt.kt
+++ b/firestore/src/main/java/de/sipgate/federmappe/firestore/DocumentSnapshotExt.kt
@@ -3,6 +3,7 @@ package de.sipgate.federmappe.firestore
 import com.google.firebase.Timestamp
 import com.google.firebase.firestore.DocumentSnapshot
 import de.sipgate.federmappe.common.DefaultSerializersModule
+import de.sipgate.federmappe.common.ErrorHandler
 import de.sipgate.federmappe.common.toObjectWithSerializer
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.modules.SerializersModule
@@ -10,12 +11,12 @@ import kotlinx.serialization.modules.SerializersModule
 @ExperimentalSerializationApi
 inline fun <reified T : Any> DocumentSnapshot.toObject(
     customSerializers: SerializersModule = DefaultSerializersModule,
-    errorHandler: (Throwable) -> T? = { throw it }): T? =
-    try {
-        data?.toObjectWithSerializer<T>(
-            customSerializers = customSerializers,
-            subtypeDecoder = { (it as? Timestamp)?.let(::FirebaseTimestampDecoder) }
-        )
-    } catch (ex: Throwable) {
-        errorHandler(ex)
-    }
+    errorHandler: ErrorHandler<T> = { throw it }
+): T? = try {
+    data?.toObjectWithSerializer<T>(
+        customSerializers = customSerializers,
+        subtypeDecoder = { (it as? Timestamp)?.let(::FirebaseTimestampDecoder) }
+    )
+} catch (ex: Throwable) {
+    errorHandler(ex)
+}
diff --git a/firestore/src/main/java/de/sipgate/federmappe/firestore/QuerySnapshotExt.kt b/firestore/src/main/java/de/sipgate/federmappe/firestore/QuerySnapshotExt.kt
index 8192645..f13f4a5 100644
--- a/firestore/src/main/java/de/sipgate/federmappe/firestore/QuerySnapshotExt.kt
+++ b/firestore/src/main/java/de/sipgate/federmappe/firestore/QuerySnapshotExt.kt
@@ -3,6 +3,7 @@ package de.sipgate.federmappe.firestore
 import com.google.firebase.Timestamp
 import com.google.firebase.firestore.QuerySnapshot
 import de.sipgate.federmappe.common.DefaultSerializersModule
+import de.sipgate.federmappe.common.ErrorHandler
 import de.sipgate.federmappe.common.toObjectWithSerializer
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.modules.SerializersModule
@@ -10,14 +11,13 @@ import kotlinx.serialization.modules.SerializersModule
 @ExperimentalSerializationApi
 inline fun <reified T : Any> QuerySnapshot.toObject(
     customSerializers: SerializersModule = DefaultSerializersModule,
-    errorHandler: (Throwable) -> T? = { throw it }
-): List<T?> =
-    map { documentSnapshot ->
-        try {
-            documentSnapshot.data.toObjectWithSerializer(
-                customSerializers = customSerializers,
-                subtypeDecoder = { (it as? Timestamp)?.let(::FirebaseTimestampDecoder) })
-        } catch (ex: Throwable) {
-            errorHandler(ex)
-        }
+    errorHandler: ErrorHandler<T> = { throw it }
+): List<T?> = map { documentSnapshot ->
+    try {
+        documentSnapshot.data.toObjectWithSerializer(
+            customSerializers = customSerializers,
+            subtypeDecoder = { (it as? Timestamp)?.let(::FirebaseTimestampDecoder) })
+    } catch (ex: Throwable) {
+        errorHandler(ex)
     }
+}
diff --git a/realtimedb/src/main/kotlin/de/sipgate/federmappe/realtimedb/DataSnapshotExt.kt b/realtimedb/src/main/kotlin/de/sipgate/federmappe/realtimedb/DataSnapshotExt.kt
index 5306ecd..c067cf8 100644
--- a/realtimedb/src/main/kotlin/de/sipgate/federmappe/realtimedb/DataSnapshotExt.kt
+++ b/realtimedb/src/main/kotlin/de/sipgate/federmappe/realtimedb/DataSnapshotExt.kt
@@ -1,6 +1,7 @@
 package de.sipgate.federmappe.realtimedb
 
 import com.google.firebase.database.DataSnapshot
+import de.sipgate.federmappe.common.ErrorHandler
 import de.sipgate.federmappe.common.StringMapToObjectDecoder
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.KSerializer
@@ -11,7 +12,7 @@ import kotlinx.serialization.serializer
 @ExperimentalSerializationApi
 inline fun <reified T : Any> DataSnapshot.toObject(
     customSerializers: SerializersModule = EmptySerializersModule(),
-    crossinline errorHandler: (Throwable) -> T? = { throw it }
+    crossinline errorHandler: ErrorHandler<T> = { throw it }
 ): T? = try {
     toObjectWithSerializer(customSerializers = customSerializers)
 } catch (ex: Throwable) {
diff --git a/realtimedb/src/main/kotlin/de/sipgate/federmappe/realtimedb/DatabaseReferenceExt.kt b/realtimedb/src/main/kotlin/de/sipgate/federmappe/realtimedb/DatabaseReferenceExt.kt
index ae003a6..e582158 100644
--- a/realtimedb/src/main/kotlin/de/sipgate/federmappe/realtimedb/DatabaseReferenceExt.kt
+++ b/realtimedb/src/main/kotlin/de/sipgate/federmappe/realtimedb/DatabaseReferenceExt.kt
@@ -1,17 +1,18 @@
 package de.sipgate.federmappe.realtimedb
 
 import com.google.firebase.database.DatabaseReference
+import de.sipgate.federmappe.common.ErrorHandler
 import kotlinx.coroutines.tasks.await
 import kotlinx.serialization.ExperimentalSerializationApi
 
 @ExperimentalSerializationApi
 suspend inline fun <reified T : Any> DatabaseReference.toObject(
-    crossinline errorHandler: (Throwable) -> T? = { throw it }
+    crossinline errorHandler: ErrorHandler<T> = { throw it }
 ): T? = get().await().toObject<T>(errorHandler = errorHandler)
 
 @ExperimentalSerializationApi
 suspend inline fun <reified T : Any> DatabaseReference.toObjects(
-    crossinline errorHandler: (Throwable) -> T? = { throw it }
+    crossinline errorHandler: ErrorHandler<T> = { throw it }
 ): List<T> = get().await().children.mapNotNull { childSnapshot ->
     childSnapshot.toObject<T>(errorHandler = errorHandler)
 }