The filter() method creates a new array
containing only certain elements from
the array it is invoked on.
filter() accepts a function as an argument.
It invokes that function on each
element of an array.
In the example given above,
numbers.filter(number => number % 2 === 0)
returns an array that contains
only those elements of numbers
that returns true when
passed as the argument to
number => number % 2 === 0.