$re = '/(?<=attrs={|,)([^:}]*):([^:},]*)(?=}|,)/s';
$str = 'this.mk(attrs={keyCollection.key: 40}))
this.mk(attrs={keyCollection.key: 50, override.key: override.value})
this.mk(attrs={keyCollection.key: 60,
override.key: override.value})';
preg_match_all($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