JSFiddle - React, Tailwind, and code Playground

JavaScript

BigInt.prototype.toJSON = function(){
  return this.toString();
}

const jsonReviver = (key, val) => (key === "bigIntDemo") ? BigInt(val) : val;

const origin = {
  bigIntDemo: BigInt(Number.MAX_SAFE_INTEGER) * 2n,
  number: Number.MAX_SAFE_INTEGER,
};

const json = JSON.stringify(origin);

const parsed = JSON.parse(json, jsonReviver);

console.clear();
console.log("origin", origin);
console.log("json", json);
console.log("parsed", parsed);