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I am using functional component with hooks. I need to update state in parent from a child. I am using a prop function in Parent. All works fine except my prop function is getting the previous state and not the current state. My prop function gets executed before useState hook setting current state. How can I can I wait for my call back function to be executed after useState call. I am looking for something like setState(state,callback) from class based components.

Here is the code snippet:

function Parent() {
  const [Name, setName] = useState("");
  getChildChange = getChildChange.bind(this);
  function getChildChange(value) {
    setName(value);
  }

  return <div> {Name} :
    <Child getChildChange={getChildChange} ></Child>
  </div>
}

function Child(props) {
  const [Name, setName] = useState("");
  handleChange = handleChange.bind(this);

  function handleChange(ele) {
    setName(ele.target.value);
    props.getChildChange(collectState());
  }

  function collectState() {
    return Name;
  }

  return (<div>
    <input onChange={handleChange} value={Name}></input>
  </div>);
} 

Answers

You can use useEffect/useLayoutEffect to achieve this:

const SomeComponent = () => {
  const [count, setCount] = React.useState(0)

  React.useEffect(() => {
    if (count > 1) {
      document.title = 'Threshold of over 1 reached.';
    } else {
      document.title = 'No threshold reached.';
    }
  }, [count]);

  return (
    <div>
      <p>{count}</p>

      <button type="button" onClick={() => setCount(count + 1)}>
        Increase
      </button>
    </div>
  );
};

If you want to prevent the callback from running on first render, adjust the previous version:

const SomeComponent = () => {
  const [count, setCount] = React.useState(0)

  const didMount = React.useRef(false);

  React.useEffect(() => {
    if (!didMount.current) {
      didMount.current = true;
      return;
    }

    if (count > 1) {
      document.title = 'Threshold of over 1 reached.';
    } else {
      document.title = 'No threshold reached.';
    }
  }, [count]);

  return (
    <div>
      <p>{count}</p>

      <button type="button" onClick={() => setCount(count + 1)}>
        Increase
      </button>
    </div>
  );
};

More about it over here.