Save data into a NaN (only works in V8)

nanboxing.ts

const MSB = 1 << 7;

const nanbox = (message: string): number => {
  const float = new Float32Array(1);
  const bytes = new Uint8Array(float.buffer);
  bytes[3] = ~MSB + (MSB & message.charCodeAt(0));
  bytes[2] = MSB + (~MSB & message.charCodeAt(0));
  bytes[1] = message.charCodeAt(1);
  bytes[0] = message.charCodeAt(2);

  return float[0];
};

const nunbox = (nan: number): string => {
  const float = Float32Array.from([nan]);
  const bytes = new Uint8Array(float.buffer);
  return (
    String.fromCharCode(bytes[3] & (MSB + bytes[2]) & ~MSB) +
    String.fromCharCode(bytes[1]) +
    String.fromCharCode(bytes[0])
  );
};

const message = "Sup";
const boxed = nanbox(message);
console.log(boxed); // NaN

const unboxed = nunbox(boxed);
console.log(unboxed); // Sup