function Parent () {
  this.names = ['kevin', 'daisy'];
  }

  function Child () {

  }

  Child.prototype = new Parent();

  var child1 = new Child();

  child1.names.push('yayu');

  console.log(child1.names); // ["kevin", "daisy", "yayu"]

  var child2 = new Child();

  console.log(child2.names); // ["kevin", "daisy", "yayu"]