exclide kets form object.keys code example
Example 1: javascript delete key from object
let person = {
firstname: 'John',
lastname: 'Doe'
}
console.log(person.firstname);
// expected output: "John"
delete person.firstname;
console.log(person.firstname);
// expected output: undefined
Example 2: javascript remove object key
var obj = {a: 5, b: 3};
delete obj["a"];
console.log(obj); // {b: 3}