Add default preset name if none specified.

wled00/presets.cpp

@@ -53,6 +53,7 @@ bool applyPreset(byte index, byte callMode)
 void savePreset(byte index, bool persist, const char* pname, JsonObject saveobj)
 {
   if (index == 0 || (index > 250 && persist) || (index<255 && !persist)) return;
+  char tmp[12];
   JsonObject sObj = saveobj;
 
   const char *filename = persist ? "/presets.json" : "/tmp.json";
@@ -65,7 +66,11 @@ void savePreset(byte index, bool persist, const char* pname, JsonObject saveobj)
     if (!requestJSONBufferLock(10)) return;
     #endif
     sObj = doc.to<JsonObject>();
-    if (pname) sObj["n"] = pname;
+
+    if (sObj["n"].isNull() && pname == nullptr) {
+      sprintf_P(tmp, PSTR("Preset %d"), index);
+      sObj["n"] = tmp;
+    } else if (pname) sObj["n"] = pname;
 
     DEBUGFS_PRINTLN(F("Save current state"));
     serializeState(sObj, true);