calculate JSON.stringify(obj) to sum value?

In my local storage I have some score value stored in array

var obj = localStorage.getItem("scoreList")

output

[0,10,10,0,10]

I want sum of this value like and return to data value

sum = 30

I have tried to convert into string value

var string = JSON.stringify(obj);
output "[0,10,10,0,10]"

How can I execute this sum value ?

>Solution :

localStorage.getItem("scoreList").replace(/(\[|\])/g, '').split(",").map(x => parseFloat(x)).reduce((a,b) => a+b, 0)

a simple way:

JSON.parse(localStorage.getItem("scoreList")).reduce((x, y) => x + y)