stealing.js

function A(name) { 
  this.name = name || 'Christiano';
  return this.name;
}

function B() { 
  this.surname = 'Milfont';
  
  this.getName = function() {
    return `${this.name} - ${this.surname}`;
  }
  
  this.whatever = A;
  
  this.acontece = function(name) {
   return this.whatever(); 
  }
   
}

a = new A
b = new B

b.name = b.acontece('Marcelo');