useWillUnmount.md

useWillUnmount

A hook that takes in a function to execute right before the component unmounts.

Why? 💡

• takes care of performing a callback before the component unmounts

Basic Usage:

import { Typography } from 'antd';
import useWillUnmount from 'beautiful-react-hooks/useWillUnmount';

const ComponentWillUnmount = () => {
  useWillUnmount(() => {
    console.log('Component will unmount');
  });

  return (
    <DisplayDemo title="useWillUnmount">
      <Typography.Paragraph>Check the javascript console after moving from this page</Typography.Paragraph>
    </DisplayDemo>
  );
};

<ComponentWillUnmount />

Callback setter syntax:

If the first parameter is omitted, you can use the returned function (a callback setter) to set the useWillUnmount handler. However, you must immediately invoke the callback setter.

Important: The callback setter only changes the value of the callback reference and does not trigger a component rerender. Also, avoid invoking it asynchronously

import { Typography } from 'antd';
import useWillUnmount from 'beautiful-react-hooks/useWillUnmount';

const ComponentWillUnmount = () => {
  const onUnmount = useWillUnmount();

  onUnmount(() => {
    console.log('Component will unmount');
  });

  return (
    <DisplayDemo title="useWillUnmount">
      <Typography.Paragraph>Check the javascript console after moving from this page</Typography.Paragraph>
    </DisplayDemo>
  );
};

<ComponentWillUnmount />

✅ Pro tip:

When using a React function component you should not really think of it in terms of "lifecycle".

The useWillUnmount hook is indeed intended as a shortcut to useLayoutEffect(() => () => willUnmount, []).

To deep understanding useLayoutEffect, what it is and how it should be properly used, please read "A complete guide to useLayoutEffect" by React Team

Mastering the hook

✅ When to use

• When you need to perform a function before the component has mounted

🛑 When not to use

• Avoid using this hook asynchronously since it would violate the rules of hooks
• If you're using the callback setter, make sure to invoke it immediately instead of asynchronously

Types

import { type GenericFunction } from './shared/types';
/**
 * Returns a callback setter for a callback to be performed when the component will unmount.
 */
declare const useWillUnmount: <TCallback extends GenericFunction>(callback?: TCallback | undefined) => import("./shared/types").CallbackSetter<undefined>;
export default useWillUnmount;