Two simple variants of NODE_ENV === production. Exports a boolean or a function, which turns into a noop when browserified. Best combined with uglifyify as a transform to remove dead code.
As a boolean, using a cached process.env.NODE_ENV
var inProduction = require('in-production')
if (inProduction) //..As a function, using an uncached process.env.NODE_ENV
var inProduction = require('in-production/function')
if (inProduction()) // ..With npm do:
npm install in-production