Simulated "classical inheritance" in JS

classical.js

const Parent = function(x) {
  this.x = x;
  console.log('Parent called');
};

const Child = function() {
  Parent.call(this, 'xxxxx');
  console.log('Child called');
};

Child.prototype.setX = function(x) {
  this.x = x;
};

Child.prototype = Object.create(Parent.prototype);
Child.prototype.constructor = Child;

const child = new Child;
child.x = '5dsfdadss';

console.log(child);

const SomeMixin = function() {
  console.log('Mixin called');
  this.mixin_val = 't';
};

SomeMixin.prototype.test = function() {
  this.mixin_val = 'test';
};

const Child2 = function() {
  this.child2_val = 'xxxxxxxxxxxx';
  SomeMixin.call(this);
};

Child2.prototype = Object.create(Child.prototype); 
Child2.prototype.constructor = Child2;

Child2.prototype = Object.assign(Child2.prototype, SomeMixin.prototype);

const child2 = new Child2;
child2.test();


console.log(child2);