Nodejs ftp client over http proxy

I'm using node-ftp to connect to the ftp server. How can i call ftp server in NodeJS through http proxy. here is my code:

    var client = require('ftp');
    var c = new client();
    c.on('ready', function () {
    });
    c.connect({ host: ***, user: '***', password: '***' });

via Mohammad Zare