It's not valid JSON, since the array elements aren't quoted.

If the array elements are all dates formatted like that, you could use a regular expression to extract them.

let stringarr = "[2022/07/12, 2022/08/09]"
let dates = stringarr.match(/\d{4}\/\d{2}\/\d{2}/g);
console.log(dates);

It's to much simple 😄.

As your input is a valid array in string format. So, remove [ ] brackets and split with comma (,). Then it automatically generates an array.

let stringarr = "[2022/07/12, 2022/08/09]";
let arr = stringarr.replace(/(\[|\])/g, '').split(',');

Output:

['2022/07/12', ' 2022/08/09']

what can i do then to convert it to an array

There are several ways to do that, if the format of the string stays like this. Here's an idea.

console.log(`[2022/07/12, 2022/08/09]`
  .slice(1, -1)
  .split(`, `));

Or edit to create a valid JSON string:

const dateArray = JSON.parse(
  `[2022/07/12, 2022/08/09]`
    .replace(/\[/, `["`)
    .replace(/\]/, `"]`)
    .replace(/, /g, `", "`));
    
console.log(dateArray);

Or indeed use the match method @Barmar supplied.