Ways to define modules in node

asClassv1.js

var onedep = require('one');
var self;

function AsClass(param) {
  this.param = param;
}

AsClass.prototype.doSomething(param) {
  console.log('can access',self.param);
  onedep('whatever', function() {
    console.log('can access', self.param);
  })
}

module.exports = AsClass;

asClassv2.js

var onedep = require('one');
var commonvalue;

function AsClass(initial) {
  var othervalue = 1;
  commonvalue = initial;
  
  function doSomething(value) {
    console.log(commonvalue);
  }
  
  function doSomethingElse(value) {
    console.log(othervalue);
  }
  
  return {
    exposeDoSomething: doSomething
    exposeDoSomethingElse: doSomethingElse
  }
}

module.exports = AsClass;

asClassv3.js

var onedep = require('one');

module.exports = function(initial) {
  function AsClass(intial) {
    
    this.doSomething = function(params) {
      console.log(params)
    }
  }
}