Preserve 'this' in prototype function

preserve_this_in_prototype.js

var EValidator = require('evalidator');

var mainObject = {
    propertyObject: new PropertyObject(),
    ev: new SuperEValidator()
};

/**
 * EValidator extension object
 * @constructor
 */
function SuperEValidator(){
    // EValidator Inheritance
    EValidator.apply(this, arguments);
}

SuperEValidator.prototype = Object.create(EValidator.prototype);
SuperEValidator.prototype.constructor = SuperEValidator;

SuperEValidator.prototype.method_A = function(){
    console.log('method_A called');
};

SuperEValidator.prototype.method_B = function(){
    this.method_A();
};

/**
 * Plan object
 * @constructor
 */
function PropertyObject(){}
PropertyObject.prototype.method_A = function(){
    console.log('method_A called');
};

PropertyObject.prototype.method_B = function(){
    this.method_A();
};


/*** Calling methods from MainObject ***/
mainObject.propertyObject.method_B(); // Throws Error 'MainObject doesn't have 'method_A' method
mainObject.ev.method_B(); // Throws Error 'MainObject doesn't have 'method_A' method


// Solutions:
// 1.- set var me; at global level and set it to 'this' at PropertyObject Constructor, then inside method_B use 'me' instead 'this'
// 2.- Inside method_B use 'PropertyObject.prototype' instead 'this'
// 3.- Any other one???