fix: add verification when request body is falsy (#1702)

* fix: add verification when request body is falsy

* Update index.js

* style: Update conditional check for FormData instance

Author: eduardohilariodev

packages/openapi-fetch/src/index.js

@@ -84,10 +84,10 @@ export default function createClient(clientOptions) {
     };
     if (requestInit.body) {
       requestInit.body = bodySerializer(requestInit.body);
-    }
-    // remove `Content-Type` if serialized body is FormData; browser will correctly set Content-Type & boundary expression
-    if (requestInit.body instanceof FormData) {
-      requestInit.headers.delete("Content-Type");
+      // remove `Content-Type` if serialized body is FormData; browser will correctly set Content-Type & boundary expression
+      if (requestInit.body instanceof FormData) {
+        requestInit.headers.delete("Content-Type");
+      }
     }
 
     let id;