Create multi database to dupe writes

nullboard.html

@@ -1237,6 +1237,47 @@
       }
    }
 
+   class MultiDatabase extends Database {
+      constructor()
+      {
+         super();
+         if (arguments.length < 1)
+         {
+            throw "must supply at least one database";
+         }
+         this.databases = [];
+         for (var i=0; i<arguments.length; i++)
+         {
+            this.databases.push(arguments[i]);
+         }
+      }
+
+      get(key) {
+         return this.databases[0].get(key);
+      }
+
+      set(key, value)
+      {
+         this.databases.forEach((database) => {
+            database.set(key, value);
+         });
+      }
+
+      del(key)
+      {
+         this.databases.forEach((database) => {
+            database.del(key, value);
+         });
+      }
+
+      forEach(foo)
+      {
+         this.databases[0].forEach((key) => {
+            foo(key);
+         });
+      }
+   }
+
    class NamespacedDatabase extends Database {
       constructor(namespace, database)
       {
@@ -1322,6 +1363,11 @@
    }
 
    globalStorage = new NamespacedDatabase("4", new Local());
+   globalStorage = new MultiDatabase(
+      new NamespacedDatabase("A", new Local()),
+      new NamespacedDatabase("B", new Local()),
+   );
+   globalStorage = new NamespacedDatabase("B", new Local());
 
 	/*
 	 *	poor man's error handling -- $fixme