New hook/use set state with callback

[iamdivypatel]

Summary

How did you test this change?

[meta-cla]

Hi @iamdivypatel!

Thank you for your pull request and welcome to our community.

Action Required

In order to merge any pull request (code, docs, etc.), we require contributors to sign our Contributor License Agreement, and we don't seem to have one on file for you.

Process

In order for us to review and merge your suggested changes, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

Once the CLA is signed, our tooling will perform checks and validations. Afterwards, the pull request will be tagged with CLA signed. The tagging process may take up to 1 hour after signing. Please give it that time before contacting us about it.

If you have received this in error or have any questions, please contact us at [email protected]. Thanks!

[iamdivypatel]

📦 Contributing useSetStateWithCallback to React

🔧 Overview

This document describes the custom hook useSetStateWithCallback, designed to enhance state management in React functional components by allowing a callback after state updates, similar to the setState callback in class components.

---

🪝 Hook: useSetStateWithCallback

🧠 Purpose

Enables state updates with a post-update callback in functional components.

---

🧪 Usage Example

import { useSetStateWithCallback } from 'react';

function Demo() {
  const [open, setOpen] = useSetStateWithCallback(false);

  function handleOpen() {
    setOpen(true, () => {
      alert('Dialog is now open! Value: ' + open);
    });
  }

  function handleClose() {
    setOpen(false, () => {
      alert('Dialog is now closed! Value: ' + open);
    });
  }

  return (
    <>
      <p>State: {open ? 'Open' : 'Closed'}</p>
      <button onClick={handleOpen}>Open</button>
      <button onClick={handleClose}>Close</button>
    </>
  );
}

✅ Sample Test

import React, { useEffect } from 'react';
import { create } from 'react-test-renderer';
import { useSetStateWithCallback } from '../src/useSetStateWithCallback';

function TestComponent({ onReady }) {
  const [val, setVal] = useSetStateWithCallback(0);

  useEffect(() => {
    setVal(10, (finalVal) => {
      onReady(finalVal);
    });
  }, []);

  return <div>{val}</div>;
}

test('callback executes after state update', (done) => {
  create(
    <TestComponent
      onReady={(val) => {
        expect(val).toBe(10);
        done();
      }}
    />
  );
});

---

📎 Notes

• Backward compatible with existing hooks
• Useful for scenarios like modals, form feedback, async sequences
• Not included in public export unless approved