diff --git a/src/index.ts b/src/index.ts
index e49a794..c4e5077 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -10,7 +10,13 @@ import {
   AbstractValueIterator
 } from 'abstract-level'
 
-export type LevelErrorCode = 'LEVEL_PUT_ERROR' | 'LEVEL_NOT_FOUND' | 'LEVEL_GET_ERROR' | 'LEVEL_DEL_ERROR'
+export type LevelErrorCode =
+  | 'LEVEL_PUT_ERROR'
+  | 'LEVEL_NOT_FOUND'
+  | 'LEVEL_GET_ERROR'
+  | 'LEVEL_DEL_ERROR'
+  | 'LEVEL_INVALID_VALUE'
+
 export class LevelError extends Error {
   public code: LevelErrorCode