docs: fix assemblyOptions example for React

docs/framework-integrations/react.mdx

@@ -215,21 +215,24 @@ params.
 
 ```js
 // ...
-function createUppy(userId) {
- return new Uppy({ meta: { userId } }).use(Transloadit, {
- async assemblyOptions(file) {
+function createUppy() {
+ const uppy = new Uppy();
+ uppy.use(Transloadit, {
+ async assemblyOptions() {
  // You can send meta data along for use in your template.
  // https://transloadit.com/docs/topics/assembly-instructions/#form-fields-in-instructions
- const body = JSON.stringify({ userId: file.meta.userId });
+ const { meta } = uppy.getState();
+ const body = JSON.stringify({ userId: meta.userId });
  const res = await fetch('/transloadit-params', { method: 'POST', body });
  return response.json();
  },
  });
+ return uppy;
 }
 
 function Component({ userId }) {
  // IMPORTANT: passing an initializer function to prevent Uppy from being reinstantiated on every render.
- const [uppy] = useState(() => createUppy(userId));
+ const [uppy] = useState(createUppy);
 
  useEffect(() => {
  if (userId) {

docs/uploader/transloadit.mdx

@@ -242,7 +242,7 @@ signature and return your configuration.
 
 ```js
 uppy.use(Transloadit, {
- async assemblyOptions(file) {
+ async assemblyOptions() {
  const res = await fetch('/transloadit-params');
  return res.json();
  },