how to add 1 to an objects property javascript code example

Example 1: javascript object

var	person = {
	first_name : "Marty",
  	last_name : "Mcfly",
	born : 1968,
	died : 1933,
    lovers: ["Jennifer Parker","Baines McFly"]
};

Example 2: add property to object javascript

let yourObject = {};

//Examples:
//Example 1
let yourKeyVariable = "yourKey";
yourObject[yourKeyVariable] = "yourValue";

//Example 2
yourObject["yourKey"] = "yourValue";

//Example 3
yourObject.yourKey = "yourValue";