First rotated log file should be "0"

Author: sam-lord

lib/fileRotator.js

@@ -96,15 +96,15 @@ class FileRotator extends EventEmitter {
 
     _getFileName(number, gzip) {
         const parsedPath = path.parse(this._path);
-        let base = `${parsedPath.name}.${String(number)}${parsedPath.ext}`;
+        let base = `${parsedPath.name}.${String(number - 1)}${parsedPath.ext}`;
         if (number === 0) {
             base = parsedPath.name
                 .replace('.%N', '')
                 .replace('_%N', '')
                 .replace('-%N', '')
                 .replace('%N', '') + parsedPath.ext;
         } else if (parsedPath.name.indexOf('%N') >= 0) {
-            base = parsedPath.name.replace('%N', String(number)) + parsedPath.ext;
+            base = parsedPath.name.replace('%N', String(number - 1)) + parsedPath.ext;
         }
 
         const isGzip = this._gzip && gzip;