what does ? objects do in js code example

Example 1: objects in javascript

let car = {
  engineNumber: 1234
  brand: 'BMW',
  break: function (){}
}

Example 2: js objects

// To make an object literal:
const dog = {
    name: "Rusty",
    breed: "unknown",
    isAlive: false,
    age: 7
}
// All keys will be turned into strings!

// To retrieve a value:
dog.age; //7
dog["age"]; //7

//updating values
dog.breed = "mutt";
dog["age"] = 8;