CODEWITHSUNDEEP
javascriptreactjsmaterial-uireact-hooksuse-ref
Rayden C
Rayden C

Reputation: 149

Warning findDomNode

I was trying to make a select menu with material-ui and React

const SelectLevelButton = forwardRef((props, ref) => {
  const [stateLevel, setStateLevel] = useState({
    level: "Easy"
  });

  const [stateMenu, setStateMenu] = useState({
    isOpen: false
  });

  const openMenuHandler = () => {
    setStateMenu({
      isOpen: true
    });
  };

  const closeMenuHandler = () => {
    setStateMenu({
      isOpen: false
    });
  };

  const buttonRef = useRef();

  console.log(buttonRef.current);

  return (
    <>
      <Menu open={stateMenu.isOpen} anchorEl={buttonRef.current} onClose={closeMenuHandler}>
        <MenuItem>Easy</MenuItem>
        <MenuItem>Normal</MenuItem>
        <MenuItem>Hard</MenuItem>
      </Menu>
      <div ref={buttonRef}>
        <Button onClick={openMenuHandler} color="inherit">{`Level: ${stateLevel.level}`}</Button>
      </div>
    </>
  );
});

export default SelectLevelButton;

but when i click on the button to open the menu in console i get this warning: Warning: findDOMNode is deprecated in StrictMode. findDOMNode was passed an instance of Transition which is inside StrictMode. Instead, add a ref directly to the element you want to reference.

How can i solved that?

Upvotes: 2

Views: 3052

Answers (1)

Mik
Mik

Reputation: 71

anchorEl reference in Menu is undefined, as you get it from buttonRef.current undefined at start. So it uses findDOMNode instead. See Material-UI docs how to get the reference before opening Menu.

You need to change your code like that, (not tested) :

const SelectLevelButton = forwardRef((props, ref) => {
  const [anchorEl, setAnchorEl] = React.useState(null);
  const [stateLevel, setStateLevel] = useState({
    level: "Easy"
  });

  const [stateMenu, setStateMenu] = useState({
    isOpen: false
  });

  const openMenuHandler = event => {
    setAnchorEl(event.currentTarget);
    setStateMenu({
      isOpen: true
    });
  };

  const closeMenuHandler = () => {
    setStateMenu({
      isOpen: false
    });
  };

  const buttonRef = useRef(); // No need for that

  console.log(buttonRef.current);

  return (
    <>
      <Menu open={stateMenu.isOpen} anchorEl={anchorEl} onClose={closeMenuHandler}>
        <MenuItem>Easy</MenuItem>
        <MenuItem>Normal</MenuItem>
        <MenuItem>Hard</MenuItem>
      </Menu>
      <div ref={buttonRef}>
        <Button onClick={openMenuHandler} color="inherit">{`Level: ${stateLevel.level}`}</Button>
      </div>
    </>
  );
});

export default SelectLevelButton;

Upvotes: 1

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