node lodash extend

base.page.object.js

'use strict';

var BasePageObject = function(arg1) {
  this.arg1 = arg1;
};

BasePageObject.prototype.helloWorld = function() {
  console.log('Hello, World!');
};

module.exports = BasePageObject;

my.page.object.js

'use strict';

var _ = require('lodash'), 
  BasePageObject = require('./base.page.object');

var MyPageObject = function(arg1, arg2) {
  // If needed, this is similar to super()
  BasePageObject.call(this, arg1);
  
  this.arg2 = arg2;
};

MyPageObject.prototype = _.extend(BasePageObject.prototype, {
  printArgs: function() {
    console.log(this.arg1, this.arg2);
  }
});

module.exports = MyPageObject;