Usort with PHP7 Spaceship vs PHP5.6

usort.php

<?php
// PHP 5.6

usort($array, function($a, $b) {
  if ($a == $b) {
    return 0;
  }
  return ($a < $b) ? -1 : 1;
});

// PHP 7 with spaceship operator

usort($array, function($a, $b) {
  return $a <=> $b;
});