Convert `"/Date()/"` dates from JSON to DateTime objects.

gistfile1.php

function convertJsonDate( $string ) {

  if ( preg_match('#^/Date\((-?\d+)([+-]\d+)?\)/$#', $string, $matches) ) {

  	$ds = intval( $matches[1] ) / 1000;
  	$dm = intval( $matches[1] ) % 1000;
  	$tz = '+000';
  	if ( isset($matches[2]) ) {
  		$tz = $matches[2];
  	}

  	if ( $dt = \DateTime::createFromFormat('U u O', $ds.' '.$dm.' '.$tz) ) {
  		$string = $dt;
  	}

  }

  return $string;
  
}