[Forminator Pro] - Use upload file as notification condition

wpmudev-forminator-upload-file-notification.php

<?php
/**
 * Plugin Name: [Forminator Pro] - Use upload file as notification condition
 * Plugin URI: https://premium.wpmudev.org/
 * Description: Use a hidden field to determine whether a file has been uploaded (as of 1.12.1.1)
 * Author: Alessandro Kaounas @ WPMUDEV
 * Author URI: https://premium.wpmudev.org/
 * Task: SLS-65
 * License: GPLv2 or later
*/

add_action( 'forminator_custom_form_submit_before_set_fields', function( $entry, $form_id, $field_data_array ){

    // User defined settings
    $form      = 10; // Define form to apply
    $upload_field = 'upload-1'; // Set upload file field
    $hidden_field = 'hidden-1'; // Set hidden input

    if ( $form_id != $form ){
        return $field_data_array;
    }

    $fields = wp_list_pluck( $field_data_array, 'name' );

    $upload_field_key = array_search( $upload_field, $fields );

    if( $upload_field_key && ! empty( $field_data_array[$upload_field_key]['value'] ) ){
        add_filter( 'forminator_custom_form_mail_data', function( $data ) use ( $upload_field_key, $hidden_field ) {
            $data[$hidden_field] = ( $upload_field_key ? 'has_file' : '' );
            return $data;
        });
    }

}, 10, 3 );