diff --git a/android/src/main/java/com/bitmovin/player/reactnative/converter/JsonConverter.kt b/android/src/main/java/com/bitmovin/player/reactnative/converter/JsonConverter.kt
index 24d057bd..17775248 100644
--- a/android/src/main/java/com/bitmovin/player/reactnative/converter/JsonConverter.kt
+++ b/android/src/main/java/com/bitmovin/player/reactnative/converter/JsonConverter.kt
@@ -1208,13 +1208,12 @@ class JsonConverter {
         /**
          * Converts any [BufferType] value into its json representation.
          * @param bufferType [BufferType] value.
-         * @return The produced JS string, or `null` if not recognized.
+         * @return The produced JS string.
          */
         @JvmStatic
-        fun fromBufferType(bufferType: BufferType?): String? = when (bufferType) {
+        fun fromBufferType(bufferType: BufferType): String = when (bufferType) {
             BufferType.ForwardDuration -> "forwardDuration"
             BufferType.BackwardDuration -> "backwardDuration"
-            else -> null
         }
 
         @JvmStatic
diff --git a/ios/RCTConvert+BitmovinPlayer.swift b/ios/RCTConvert+BitmovinPlayer.swift
index 45790355..b2074293 100644
--- a/ios/RCTConvert+BitmovinPlayer.swift
+++ b/ios/RCTConvert+BitmovinPlayer.swift
@@ -1190,16 +1190,14 @@ extension RCTConvert {
     /**
      * Converts any `BufferType` value into its json representation.
      * - Parameter bufferType: `BufferType` value.
-     * - Returns: The produced JS string, or `nil` if not recognized.
+     * - Returns: The produced JS string.
      */
-    static func toJson(bufferType: BufferType) -> String? {
+    static func toJson(bufferType: BufferType) -> String {
         switch bufferType {
         case .forwardDuration:
             return "forwardDuration"
         case .backwardDuration:
             return "backwardDuration"
-        default:
-            return nil
         }
     }