Conditional module loading in bower

child.js

module.exports = function(a){
  console.log('child got '+a)
}

parent.js

// Rename require so browserify will not be able to detect module requirement and will not bundle it
var loader = require

// On server side call parent file (as it supports require)
// On client side call built file (bundle)

if (typeof window === 'undefined') { // In node
  var $$ = loader('./child')
} else {
  var $$ = function(a) { // In browser
    console.log('use local function, got: ' + a)
  }
}

$$('from parent')