Add ContainKeyAsync

src/Blazored.SessionStorage/ISessionStorageService.cs

@@ -11,13 +11,21 @@ public interface ISessionStorageService
 
         Task<string> KeyAsync(int index);
 
+        /// <summary>
+        /// Checks if the key exists in Session Storage but does not check the value.
+        /// </summary>
+        /// <param name="key">name of the key</param>
+        /// <returns>True if the key exist, false otherwise</returns>
+        Task<bool> ContainKeyAsync(string key);
+
         Task<int> LengthAsync();
 
         Task RemoveItemAsync(string key);
 
         Task SetItemAsync<T>(string key, T data);
 
         event EventHandler<ChangingEventArgs> Changing;
+
         event EventHandler<ChangedEventArgs> Changed;
     }
-}
+}

src/Blazored.SessionStorage/ISyncSessionStorageService.cs

@@ -10,13 +10,21 @@ public interface ISyncSessionStorageService
 
         string Key(int index);
 
+        /// <summary>
+        /// Checks if the key exists in Session Storage but does not check the value.
+        /// </summary>
+        /// <param name="key">name of the key</param>
+        /// <returns>True if the key exist, false otherwise</returns>
+        bool ContainKey(string key);
+
         int Length();
 
         void RemoveItem(string key);
 
         void SetItem<T>(string key, T data);
 
         event EventHandler<ChangingEventArgs> Changing;
+
         event EventHandler<ChangedEventArgs> Changed;
     }
 }