Load a .js file?

You can save what you've currently got into Espruino with save() but there isn't room in the chip for other files. Instead you can save onto the SD card.

You can save modules into node_modules/modname.js on the SD card and can load them with require('modname'), or you can simply load and execute any JS file from the SD card with: eval(require('fs').readFile("filepath.js­"))