Module Pattern - Killing this

car.js

var internals = {
	
	revEngine : function rev( state, engine ) {
		
	    state.timesRevved++
    
	    switch( engine ) {
	        case "v8":
	            console.log("vrooooooooom!")
	            break
	        case "v6":
	            console.log("vroooom")
	            break
	        default:
	            console.log("vroom")
	    }    
		
	},
    
}

module.exports = function createCar( engine ) {
    
    var state = {
        timesRevved: 0
    }
    
    return {
        rev : _.partial( revEngine, state, engine ),
        timesRevved : () => state.timesRevved
    }
    
}

doStuff.js

var CreateCar = require('./car')

var normalCar = CreateCar( "v6" )
console.log( normalCar.timesRevved() )
normalCar.rev()
console.log( normalCar.timesRevved() )

var fastCar = car( "v8" )
fastCar.rev()
fastCar.rev()
console.log( fastCar.timesRevved() )