Answer by Nicolas Guérinet for Node Webkit clear cache

It is now 2019 and clearCache() does function by adding the following:

var gui = require('nw.gui'); gui.App.clearCache();

or

nw.App.clearCache();

This will clear the HTTP cache in memory and the one on disk whatever your platform. I have tested it on Mac OS but maybe there can be user permission issues on Linux.

On MacOS, you can check in real time that the cache folder is emptied at ‎⁨

Mac HD⁩▸⁨Users⁩▸ youruser ▸⁨Library⁩▸⁨Caches⁩▸⁨yourapp ▸⁨Default⁩