jsnlog.js is available from NPM and has the necessary code to function as an CommonJS module:
Install jsnlog.js from NPM:
npm install jsnlog
Load jsnlog into your code:
var JL = require('jsnlog').JL;
CommonJS is normally used on the server, because it doesn't support asynchronous loading by the client over the network. However, Browserify enables you to use this on the client.