Quaternion
A utility identical to THREE.Quaternion so you don't have to BYO.
See three.js docs for more info.
import React from "react";
import { Quaternion } from "hyperfy";
export default function App() {
  const quaternion = new Quaternion().fromArray([0, 0, 0, 1]);
  console.log(quaternion);
  return <app />;
}