$re = '/(?<=(?:const\s|var\s|let\s)[^;\n]*)(?=const|var|let)/';
$str = 'const asd2 = "asd2"
const asd = "asd"; const asd = "asd" {;JUMP;} const';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php