Storing Functions in the JSON files (Solved) JavaScript NodeJS

I was trying to find solution to store also functions in Json.

const myObject = {
  x: 1,
  y: "Test",
  fff: function(x) {
    return x + 1000000;
  }
};

let jsonString = JSON.stringify(myObject, (k, v) =>
  typeof v === "function" ? "" + v : v
);
console.log(jsonString);

let parsedJson = eval(
  JSON.parse(jsonString, function(k, v) {
    if (typeof v === "string" && v.startsWith("function(") && v.endsWith("}")) {
      return eval("(" + v + ")");
    }
    return v;
  })
);

console.log(parsedJson.fff(1234));

based on: https://stackoverflow.com/questions/36517173/how-to-store-a-javascript-function-in-json