what's used more commonly, "person.age" or "person['age']"?

Answer 1

Person[age] === Array
.age === a single variable

Answer 2

"Person.age"

Answer 3

Person.age

Answer 4

Person.age .... you can do something like Person['last name'] if you want to treat the object as a hash map.. similar to the python dict, if you are familiar with that

Answer 5

person.age