lucifer/webui/src/Hooks/light.js

import {useEffect, useState} from "react";
import {subscribeToLight, unsubscribeFromLight} from "../Helpers/lights";

export default function useLights({groupId = -1, id = -1} = {}) {
  const [light, setLight] = useState(null);

  function onChange(light) {
    setLight(light);
  }

  useEffect(() => {
    const cbId = subscribeToLight(id, onChange);

    return () => {
      unsubscribeFromLight(cbId);
    };
  }, []);

  if (groupId >= 0 && light !== null) {
    return light.filter(l => l.groupId === groupId);
  }

  return light;
}