JSFiddle - React, Tailwind, and code Playground

JavaScript

//var csharpJsonSerializedString = "[\"^[0-9]{9}[A-Z0-9]{0,3}$\",\"^[A-Z]{1,3}([0-9]{6}|[0-9]{9})$\"]";

//var response = "[\"^[0-9]{9}[A-Z0-9]{0,3}$\",\"^[A-Z]{1,3}([0-9]{6}|[0-9]{9})$\"]";

var result = "[\"^[0-9]{9}[A-Z0-9]{0,3}$","^[A-Z]{1,3}([0-9]{6}|[0-9]{9})$\"]";

var jsonData = JSON.parse(result);
for (var i = 0; i < jsonData.length; i++) {
    console.log(jsonData[i]);
}