The mailchimp API is relatively straight forward so rather than a huge client library this is a simple wrapper which lets you specify the url and simply add the auth and does the request.
Supports Mailchimp API 3.0 or greater
First create a client with the appropriate options you require.
var Mailchimp = require('mailchimp-client');
var client = new Mailchimp(apiKey: 'xxx', version: "3.0");
Then perform the action you require. See the Mailchimp documentation for endpoint and param details.
client.post('lists/<listId>/subscribe', {email_address: '[email protected]', status: 'subscribed'}, function(err, member){
console.log(member); // {email: "email@example.com", euid: 'yyyyy', leid: 'yyyyyy'}
});
Note: If no callback is passed an A+ promise is returned