Download the latest release here.
This is an editor that evaluates your source text as you type. It's electron, so you have the node and browser APIs. Careful to only use code you trust.
HOW IT WORKS
Your script will get evaluated when you stop typing. Use
to get output in the right-hand panel.
To use modules from npm, just set your working directory to a place where those modules are installed. For example you can create a directory (call it whatever you want)...
mkdir ~/sandbox cd sandbox npm install preact
You can also start the app from the command line. You could create a symbolic link to the binary if you often start it from the commandline...