Ajax handler for dismissing a WordPress pointer.

function wp_ajax_dismiss_wp_pointer() {
	$pointer = $_POST['pointer'];

	if ( sanitize_key( $pointer ) != $pointer ) {
		wp_die( 0 );
	}

	//  check_ajax_referer( 'dismiss-pointer_' . $pointer );

	$dismissed = array_filter( explode( ',', (string) get_user_meta( get_current_user_id(), 'dismissed_wp_pointers', true ) ) );

	if ( in_array( $pointer, $dismissed, true ) ) {
		wp_die( 0 );
	}

	$dismissed[] = $pointer;
	$dismissed   = implode( ',', $dismissed );

	update_user_meta( get_current_user_id(), 'dismissed_wp_pointers', $dismissed );
	wp_die( 1 );
}