in node.js, using ssl with more than one domain name with one ip address
used to Apache in Linux where each domain name using ssl requires its own ip address.
is this still true if using node.js and not using Apache at all?
The same limitations apply in node.js as in Apache -- they're nothing to do with the particular server software you're using, they're inherent in the http and TLS/SSL protocols.
Having said that, there are two ways to run SSL for multiple domains from a single IP address. I don't know the status of node.js support for either of these, but it shouldn't matter for the first alternative.
First, you can get a single SSL certificate that covers all of the domain names you want to use -- either a wildcard if they're all subdomains of the same domain or one that uses Subject Alternative Names (SAN) if they're not. Note that SAN is not supported by some older web browsers, especially on some smartphones.
Second, you can use Server Name Indication (SNI) to configure multiple SSL certificates, as it extends the SSL protocol to make the hostname available to the server before it's done the key exchange. Browser support for SNI is not as good as for SAN, and in particular it doesn't work with any Internet Explorer version on Windows XP.