diff --git a/src/Logger.ts b/src/Logger.ts
index fd847b4..cd7cd94 100644
--- a/src/Logger.ts
+++ b/src/Logger.ts
@@ -159,7 +159,7 @@ export default class Logger {
     }
 
     levelToValue(level: string) {
-        return LogLevel[level] ? LogLevel[level] : LogLevel.debug;
+        return LogLevel[level] == "undefined" ? LogLevel.debug : LogLevel[level];
     }
 
     log(level: string, ...args) {