JSFiddle - React, Tailwind, and code Playground

JavaScript

function A() {}

     A.prototype._data = [];

     A.prototype.add = function(rec) {
       this.__proto__._data.push(rec);
     }

     A.prototype.get = function() {
       if(typeof this.__proto__.constructor.prototype.get == 'function')
       {
         return this.__proto__.constructor.prototype.get().concat(this.__proto__._data);
       }
       else
       {
         return this.__proto__._data || [];
       }
     }

     function B() {}
     B.prototype = Object.create(A.prototype, { constructor: { value: B }});
     B.prototype._data = [];

     var a = new A(), b = new B();

     a.add('aa');
     b.add('bb');
     console.log(b.get()); // [aa, bb]

     a.add('aaaa');
     console.log(b.get()); // [aa, aaaa, bb]