Node.js and sha1

http://www.php.net/manual/en/function.sha1.php

string sha1 ( string $str [, bool $raw_output = false ] )

If the raw_output option is set to TRUE, then instead of sha1 digest, a raw binary format of 20 is returned, otherwise the return value will be a hexadecimal number of 40 characters.

crypto = require("crypto");
console.log( new Buffer(crypto.createHash('sha1').update("some text").digest()).toString('base64') );
// N8KqY8OHc8KYw5lURzJiw6HCoAV8HmMuw5p3
console.log( new Buffer(crypto.createHash('sha1').update("some text").digest("hex")).toString('base64') );
// MzdhYTYzYzc3Mzk4ZDk1NDQ3MzI2MmUxYTAwNTdjMWU2MzJlZGE3Nw==
console.log( new Buffer(crypto.createHash('sha1').update("some text").digest("base64")).toString('base64') );
// TjZwangzT1kyVlJITW1MaG9BVjhIbU11Mm5jPQ==

<?php
echo base64_encode(sha1("some text"));
// MzdhYTYzYzc3Mzk4ZDk1NDQ3MzI2MmUxYTAwNTdjMWU2MzJlZGE3Nw==
echo base64_encode(sha1("some text", true)); // <-- how to reproduce it on the nodejs?
// N6pjx3OY2VRHMmLhoAV8HmMu2nc=
?>