Let’s say we received an array of users in the form {id:..., name:..., age:... }.
Create a function groupById(arr) that creates an object from it, with id as the key, and array items as values
You have an array of user objects, each one has name, surname and id.
Write the code to create another array from it, of objects with id and fullName, where fullName is generated from name and surname.
We have an array of strings arr. We’d like to have a sorted copy of it, but keep arr unmodified.
Create a function copySorted(arr) that returns such a copy.