Add possibility to pass in additional FormData fields via data prop (#8)

Author: rastapasta

README.md

@@ -105,6 +105,12 @@ abortUpload('file://some-local-file.jpg');
     <td>Optional</td>
     <td>The HTTP method for the request. Defaults to "POST".</td>
   </tr>
+  <tr>
+    <td>data</td>
+    <td>object</td>
+    <td>Optional</td>
+    <td>An object of additional FormData fields to be set with the request.</td>
+  </tr>
   <tr>
     <td>headers</td>
     <td>Headers</td>
@@ -163,7 +169,7 @@ useFileUpload({ headers });
 ```
 
 </td>
-  </tr>  
+  </tr>
   <tr>
     <td>onError</td>
     <td>function</td>
@@ -196,7 +202,7 @@ useFileUpload({ headers });
 ```
 
 </td>
-  </tr> 
+  </tr>
 </tbody>
 </table>
 

src/hooks/useFileUpload.ts

@@ -12,6 +12,7 @@ export default function useFileUpload<T extends UploadItem = UploadItem>({
   method = 'POST',
   headers,
   timeout,
+  data,
   onProgress,
   onDone,
   onError,
@@ -26,6 +27,10 @@ export default function useFileUpload<T extends UploadItem = UploadItem>({
       const formData = new FormData();
       formData.append(field, item);
 
+      if (data)
+        for (const key in data)
+          formData.append(key, data[key]);
+
       const xhr = new XMLHttpRequest();
 
       xhr.open(method, url);

src/types.ts

@@ -33,6 +33,7 @@ export type FileUploadOptions<T extends UploadItem = UploadItem> = {
   method?: string;
   headers?: Headers;
   timeout?: number;
+  data?: {[key: string]: string};
   onProgress?: (data: OnProgressData<T>) => void;
   onDone?: (data: OnDoneData<T>) => void;
   onError?: (data: OnErrorData<T>) => void;