AffiliateWP - Add the customer's first name, last name and email who the affiliate referred as columns in the exported referrals .csv file

gistfile1.php

<?php

/**
 * Add new columns to the exported referrals CSV file for the customer's first name, last name and email address
 */
function affwp_custom_export_referrals_csv_cols( $cols ) {
	$cols['customer_first_name'] = 'Customer First Name';
	$cols['customer_last_name']  = 'Customer Last Name';
	$cols['customer_email']      = 'Customer Email';

	return $cols;
}
add_filter( 'affwp_export_csv_cols_referrals', 'affwp_custom_export_referrals_csv_cols' );

/**
 * Add the customer's first name, last name and email address to our new csv columns
 */
function affwp_custom_export_get_data_referrals( $data ) {
	foreach ( $data as $key => $d ) {
		// get EDD payment user info
		$payment_user_info   = edd_get_payment_meta_user_info( $data[$key]['reference'] );

		$customer_first_name = isset( $payment_user_info['first_name'] ) ? $payment_user_info['first_name'] : '';
		$customer_last_name  = isset( $payment_user_info['last_name'] ) ? $payment_user_info['last_name'] : '';
		$customer_email      = isset( $payment_user_info['email'] ) ? $payment_user_info['email'] : '';

		$data[$key]['customer_first_name'] = $customer_first_name;
		$data[$key]['customer_last_name']  = $customer_last_name;
		$data[$key]['customer_email']      = $customer_email;
	}

	return $data;
}
add_filter( 'affwp_export_get_data_referrals', 'affwp_custom_export_get_data_referrals' );