useEffect componentDidMount and componentWillUnmount

useEffect

useEffect(() => {
      const fetchContainerData = async () => {
        try {
          const result = await SomethingService.getSomething();
          setSomething(result);
        } catch (error) {
          console.error('ERROR: ', error);
        }
      };
      fetchContainerData();
      return function cleanup() {
        props.clearStuff();
      };

  }, []);