five-for-the-future/plugins/wporg-5ftf/includes/endpoints.php

<?php
/**
 * Handle submissions to admin-ajax.php.
 */

namespace WordPressDotOrg\FiveForTheFuture\Endpoints;

use WordPressDotOrg\FiveForTheFuture\{ Contributor, PledgeForm };

add_action( 'wp_ajax_manage_contributors', __NAMESPACE__ . '\handler' );

/**
 * Handle the AJAX request.
 */
function handler() {
	check_ajax_referer( 'manage-pledge', '_ajax_nonce' );

	$action = filter_input( INPUT_POST, 'manage_action' );
	$pledge_id = filter_input( INPUT_POST, 'pledge_id', FILTER_VALIDATE_INT );
	$contributor_id = filter_input( INPUT_POST, 'contributor_id', FILTER_VALIDATE_INT );

	switch ( $action ) {
		case 'resend-contributor-confirmation':
			$contribution = get_post( $contributor_id );
			PledgeForm\send_contributor_confirmation_emails( $pledge_id, $contributor_id );
			wp_die( wp_json_encode( [
				'success' => true,
				'message' => sprintf( __( 'Confirmation email sent to %s.', 'wporg-5ftf' ), $contribution->post_title ),
			] ) );
			break;

		case 'remove-contributor':
			// Trash contributor.
			Contributor\remove_contributor( $contributor_id );
			wp_die( wp_json_encode( [
				'success' => true,
				'contributors' => Contributor\get_pledge_contributors_data( $pledge_id ),
			] ) );
			break;

		case 'add-contributor':
			$new_contributors = PledgeForm\parse_contributors( $_POST['contributors'] );
			if ( is_wp_error( $new_contributors ) ) {
				wp_die( wp_json_encode( [
					'success' => false,
					'message' => $new_contributors->get_error_message(),
				] ) );
			}
			Contributor\add_pledge_contributors( $pledge_id, $new_contributors );

			// Fetch all contributors, now that the new ones have been added.
			$contributors = Contributor\get_pledge_contributors_data( $pledge_id );

			wp_die( wp_json_encode( [
				'success' => true,
				'contributors' => $contributors,
			] ) );
			break;
	}

	// No matching action, we can just exit.
	wp_die();
}