New Array Methods

Question 1

What is Array.prototype.filter useful for?

Answer 1

Used for filtering arrays.
Array.filter(callback function returning BOOLEAN)
Array.filter(number => number % 2 === 0)

Question 2

What is Array.prototype.map useful for?

Answer 2

Used to transform exisiting arrays.
Array.map(callback function returning value)
Array.map(number => number *2)

Question 3

What is Array.prototype.reduce useful for?

Answer 3

reduces the array (accumulate)
(accumulator, currentValue) => {
  return accumulator + currentValue;
}
Array.reduce(callback function, initialValue)