What does it mean to mutate the original object?

Question

JavaScript

According to the task, there is a function:

function foo(object: Indexed){
}

you need to mutate the resulting object, write values ​​​​to it, and then return it from the function

Answer 1

Mutate == Modify, just change/remove existing object fields, add new ones, and return the object in return

Answer 2

function mutateObject(object) {
  delete object.a;

  return object;
}
const object = {a: 1};
const result = mutateObject(object);
console.log(result) // {}