[FIX] return error cause

src/print.js

@@ -133,7 +133,8 @@ const doPrint = (socket, request) => {
         error: e => {
             socket.emit(SHOW_PRINT_STATUS, {
                 status: 'error',
-                printer: request.printer
+                printer: request.printer,
+                cause: e
             })
         }
     })