Where is the logic of react hooks?

Question

Recently I've started reading react hooks code and I see this.

function useState(initialState) {
  var dispatcher = resolveDispatcher();
  return dispatcher.useState(initialState);
}
function useReducer(reducer, initialArg, init) {
  var dispatcher = resolveDispatcher();
  return dispatcher.useReducer(reducer, initialArg, init);
}
function useRef(initialValue) {
  var dispatcher = resolveDispatcher();
  return dispatcher.useRef(initialValue);
}
function useEffect(create, deps) {
  var dispatcher = resolveDispatcher();
  return dispatcher.useEffect(create, deps);
}
function useLayoutEffect(create, deps) {
  var dispatcher = resolveDispatcher();
  return dispatcher.useLayoutEffect(create, deps);
}
function useCallback(callback, deps) {
  var dispatcher = resolveDispatcher();
  return dispatcher.useCallback(callback, deps);
}
function useMemo(create, deps) {
  var dispatcher = resolveDispatcher();
  return dispatcher.useMemo(create, deps);
}
function useImperativeHandle(ref, create, deps) {
  var dispatcher = resolveDispatcher();
  return dispatcher.useImperativeHandle(ref, create, deps);
}
function useDebugValue(value, formatterFn) {
  {
    var dispatcher = resolveDispatcher();
    return dispatcher.useDebugValue(value, formatterFn);
  }
}

The dispatcher is an object that initialized by resolveDispatcher().

function resolveDispatcher() {
  var dispatcher = ReactCurrentDispatcher.current;

  if (!(dispatcher !== null)) {
    {
      throw Error( "Invalid hook call. Hooks can only be called inside of the body of a function component..." );
    }
  }

  return dispatcher;
}

and ReactCurrentDispatcher is a object with one property that called current .

var ReactCurrentDispatcher = {
  /**
   * @internal
   * @type {ReactComponent}
   */
  current: null
};

now my question is how and where react handles the logic of hooks? where is the logic of useImperativeHandle or...?

Answer 1

In general, to answer questions like this I clone the repo and use ag or git grep :

(react) $ git grep useImperativeHandle
[...]
packages/react-reconciler/src/ReactFiberHooks.new.js:    useImperativeHandle<T>(
[...]

That leads me to these mappings right here – the code for useImperativeHandle , for example, seems to be these three functions .

Understanding how they work and interact with the React fiber system is another rabbit hole.