How to convert an object?

Question

JavaScript

Hello!
How to add a new value to an object while keeping the old data.
For example:
I have an array of object with data:

interface Chelsea {
   name: string;
   age: number;
}
data = [
   {"name": "Terry", "age": 20},
   {"name": "Lampard", "age": 18},
   {"name": "Drogba", "age": 15},
];

Now I want to do the following, add country field, do it via inheritance

interface Chelsea2 extends Chelsea {
  country: string;
}

data = [
   {"name": "Terry", "age": 20, "city": "England"},
   {"name": "Lampard", "age": 18, "city": "England"},
   {"name": "Drogba", "age": 15, "city": "Cote Divuar"},
];

Thanks

Answer 1

So? Or what are you asking? And what do you want from inheritance?

data.forEach(function(e) {
  e.country = 'Hello world';
})

https://jsfiddle.net/t3e61bu5/

Answer 2

Why is there inheritance?

var data = [
   {"name": "Terry", "age": 20, "city": "England"},
   {"name": "Lampard", "age": 18, "city": "England"},
   {"name": "Drogba", "age": 15, "city": "Cote Divuar"},
];

Object.defineProperty(data, 'country', {value: 'string'});

console.log("data.country= ", data.country);

An array is also an object.