diff --git a/docbits/40_interface.md b/docbits/40_interface.md
index fc334d3..dd7bf49 100644
--- a/docbits/40_interface.md
+++ b/docbits/40_interface.md
@@ -21,7 +21,7 @@ Parse options are described in the [Parsing Options](#parsing-options) section.
 `XLSX.writeFile(wb, filename, write_opts)` attempts to write `wb` to `filename`.
 In browser-based environments, it will attempt to force a client-side download.
 
-`XLSX.writeFileAsync(filename, wb, o, cb)` attempts to write `wb` to `filename`.
+`XLSX.writeFileAsync(wb, filename, o, cb)` attempts to write `wb` to `filename`.
 If `o` is omitted, the writer will use the third argument as the callback.
 
 `XLSX.stream` contains a set of streaming write functions.