How do I convert (1,2,3) to a JSON object like [1,2,3] in javascript using jsonurl?

I’m trying to use https://github.com/jsonurl/jsonurl-js to achieve this.
I’ve tried the following code but I keep getting the result of 23.

const test = (1,2,3,23)
const testJSON = JsonURL.parse(test)
console.log(testJSON[2])

I would like to store all values of test in testJSON and access each individual item by its index.