Required Uploader

Since a file can be loaded via Drag & Drop, it is not possible to use the native required attribute to check for mandatory files.

However, this check can be performed using the data-has-values attribute added dynamically to the .fupl-wrapper element.

First, mark an uploader as required adding the relative attribute to the original input[type=file] element (you can also add the data-required="true" attribute to the main uploader container).

Then, check for data-has-values (true or false) on form submit.
You can use the src-utilities/check_required_uploader.js script to quickly add a check function. The script is also located in the dist/utilities folder as ESM and UMD.

Look for more info at Recipes: required Uploader in the README page.

To test the script, submit the form without the required image.