javascript - React Warning: Cannot update a component from inside the function body of a different component

Question

I am using Redux with Class Components in React. Having the below two states in Redux store.

{ spinner: false, refresh: false }

In Parent Components, I have a dispatch function to change this states.

class App extends React.Component {
  reloadHandler = () => {
    console.log("[App] reloadComponent");

    this.props.onShowSpinner();
    this.props.onRefresh();
  };

  render() {
    return <Child reloadApp={this.reloadHandler} />;
  }
}

In Child Component, I am trying to reload the parent component like below.

class Child extends React.Component {
  static getDerivedStateFromProps(props, state) {
    if (somecondition) {
      // doing some redux store update
      props.reloadApp();
    }
  }

  render() {
    return <button />;
  }
}

I am getting error as below.

Warning: Cannot update a component from inside the function body of a different component.

How to remove this warning? What I am doing wrong here?

question from:https://stackoverflow.com/questions/60526786/react-warning-cannot-update-a-component-from-inside-the-function-body-of-a-diff

Answer 1

For me I was dispatching to my redux store in a React Hook. I had to dispatch in a useEffect to properly sync with the React render cycle:

export const useOrderbookSubscription = marketId => {
  const { data, error, loading } = useSubscription(ORDERBOOK_SUBSCRIPTION, {
    variables: {
      marketId,
    },
  })

  const formattedData = useMemo(() => {
    // DISPATCHING HERE CAUSED THE WARNING
  }, [data])

  // DISPATCHING HERE CAUSED THE WARNING TOO

  // Note: Dispatching to the store has to be done in a useEffect so that React
  // can sync the update with the render cycle otherwise it causes the message:
  // `Warning: Cannot update a component from inside the function body of a different component.`
  useEffect(() => {
    orderbookStore.dispatch(setOrderbookData(formattedData))
  }, [formattedData])

  return { data: formattedData, error, loading }
}