Array Iterators

Question 1

Returns an iterator that contains key/value pairs of each index in the array

Answer 1

array.entries()

Question 2

When you want to transform elements in an array.

Answer 2

array.map()

Question 3

When you want to select a subset of multiple elements from an array.

Answer 3

array.filter() (immutable - creates a new array)

Question 4

When you want to select a single element from an array.

Answer 4

array.find()

Question 5

When you want derive a single value from multiple elements in an array.

Answer 5

array.reduce()

Question 6

When you need to execute a function for each individual element in an array. Only use when you can’t use a more sophisticated tool.

Answer 6

array.forEach()

Question 7

Loop over an Array

Answer 7

array.forEach() or for/of, or simple for statement

Question 8

Check if all elements are even or odd

Answer 8

array.every()

Question 9

When you want to select a single element’s index from an array

Answer 9

array.findIndex()