30 seconds of React

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useNavigatorOnLine

hooksstateeffectintermediate

A hook that returns if the client is online or offline.

  • Create a function, getOnLineStatus, that uses the NavigatorOnLine web API to get the online status of the client.
  • Use the React.useState() hook to create an appropriate state variable, status, and setter.
  • Use the React.useEffect() hook to add listeners for appropriate events, updating state, and cleanup those listeners when unmounting.
  • Finally return the status state variable.
const getOnLineStatus = () =>
  typeof navigator !== "undefined" && typeof navigator.onLine === "boolean"
    ? navigator.onLine
    : true;

const useNavigatorOnLine = () => {
  const [status, setStatus] = React.useState(getOnLineStatus());

  const setOnline = () => setStatus(true);
  const setOffline = () => setStatus(false);

  React.useEffect(() => {
    window.addEventListener("online", setOnline);
    window.addEventListener("offline", setOffline);

    return () => {
      window.removeEventListener("online", setOnline);
      window.removeEventListener("offline", setOffline);
    };
  }, []);

  return status;
};