Best way to stream base64 encoded string to a web client

I would like to serve up a minified single HTML (including CSS, JS, images, etc.) from my Espruino. To minimize space, I'm going to gzip the resulting file and use the Content-Encoding HTTP header when serving it up.

I'm also thinking about inlining this gzip file in my Espruino JS code, and base64 encode it. What is the most memory efficient way to stream this from the Espruino, and not decode the whole string into memory first?

Or is there a better idea to do this? I don't have an SD card storage, just the flash of my ESP8266 board.