convert-to-id.php

<?php 

/**
 * Convert String to ID
 *
 * @param string $string
 * @return string
 */
function zawp_convert_to_id( $string ) {
  // Lower case everything
  $string = strtolower( $string );
  // Make alphanumeric (removes all other characters)
  $string = preg_replace( "/[^a-z0-9_\s-]/", "", $string );
  // Clean up multiple dashes or whitespaces
  $string = preg_replace( "/[\s-]+/", " ", $string );
  // Convert whitespaces and underscore to dash
  $string = preg_replace( "/[\s_]/", "-", $string );
  return $string;
}