ES6+

Question 1

Generate a matrix from [‘a’, ‘b’, ‘c’] and [1, 2, 3]

Answer 1

[for (row in letters) [for (col in numbers) row + col]]

Question 2

When do you use let inside an array comprehension?

Answer 2

When it’s not wrapped in an array.

for (let a of list) log(a)

vs.

[for (a of list) a]