git clone https://github.com/kjunichi/keycastjs.git
cd keycastjs
npm install
start KeyCastJs.app.
open KeyCastJs-darwin-x64/KeyCastJs.app
The System Preferences is shown.check the box which named KeyCastJs.
reopen the app.
open KeyCastJs-darwin-x64/KeyCastJs.app
This software is released under the MIT License, see LICENSE.txt.
Enjoy!