尝试清除/清空/删除/设置回初始 state 时，React setState 挂钩不起作用

Question

I have a clearState function which sets some useState hooks back to their initial state when the restart button is clicked. However, they say that my setState is not a function. Please check code below:

App.js

...
const [question, setQuestion] = useState(0);
const [response, setResponse] = useState({});
const [answer, setAnswer] = useState({});
const [answerId, setAnswerId] = useState({});
...

Modal.js

const Modal = ({
  setResponse,
  setAnswer,
  setAnswerId,
  setQuestion,
  setAnswerNameArr,
}) => {
  const [open, setOpen] = useState(false);

  const clearState = () => {
    setOpen(false); //works
    setQuestion(0); //works
    setAnswer({}); //does not work
    setAnswerId({});
    setResponse({});
    setAnswerNameArr([]);
  };

...

  return (
    <Modal
       ...
    >
      ...
        <Button
           onClick={()=>handleSubmit()}
        >
           Restart
        </Button>
    </Modal>
  );
};

export default Modal;

The error:

Uncaught TypeError: setAnswer is not a function

Thanks in advance.

Answer 1

It looks like you aren't passing your state setting hooks in to your <Modal> so they're not available.

It isn't a good idea to do that anyway, tbh. If you need a child to affect the state of a parent it would be better to pass a single call-back:

const Modal = ({
      onSubmitCb
}) => {
  const [open, setOpen] = useState(false);

  const clearState = () => {
    setOpen(false); //works
    setQuestion(0); //works
    onSubmitCb && onSubmitCb()
  };

...

  return (
    <Modal>
      ...
        <Button
           onClick={()=>handleSubmit()}
        >
           Restart
        </Button>
    </Modal>
  );
};

and in your parent:

const App = ()=>{
    const clearState = () => {
        setAnswer({});
        setAnswerId({});
        setResponse({});
        setAnswerNameArr([]);
  };
  
  .... 

  return {
      <Modal ... onSubmitCb={clearState} />
   }
}