How does +x in an arrow function returns an array of numbers?

Asked Feb 16 '20 at 07:15

Active Feb 16 '20 at 07:19

Viewed 30 times

I saw someone wrote an arrow function in a way that I have never seen before.

function reverseArr(num) {
return String(num)
.split("")
.reverse()
.map(x => +x);
}

console.log(reverseArr(1234)); // [4, 3, 2, 1]

What does the +x do to the array? When I removed the + sign, I got an array of string instead.

// ["4", "3", "2", "1"]

asked Feb 16 '20 at 07:15

Fitri Rozi

It doesn't nothing to the **array**, `map` runs a function against each member of the array. The `+` operator isn't applied to the array itself. – Quentin Feb 16 '20 at 07:21
split("") will return array of string and +x will be converted to number – Refael Feb 16 '20 at 07:21
1

It's a Unary Operator which convert string to a number. https://jsbin.com/rujoforagu/edit?js,console – Junius L. Feb 16 '20 at 07:23
@Quentin Sorry, I was wrong. I edited. – Refael Feb 16 '20 at 07:25

0 Answers0