Reimplement react hooks

re-react-hook.js

const hookMap = new WeakMap();

let currentContext = null;
let currentIndex = 0;

function load(component) {
  if (!hookMap.has(component)) {
    hookMap.set(component, []);
  }

  currentContext = hookMap.get(component);
  currentIndex = 0;

  console.info('switched to context:', currentContext);
  component();
}

function createHook(initValue) {
  const hook = {
    value: initValue,
    setValue(newValue) {
      hook.value = newValue;
    },
  }

  return hook;
}

function useHook(initValue) {
  if (!currentContext[currentIndex]) {
    currentContext[currentIndex] = createHook(initValue);
  }

  const { value, setValue } = currentContext[currentIndex++];

  return [value, setValue];
}

function ComponentA() {
  const [count, setCount] = useHook(10);
  console.log('[A] count:', count);
  setCount(count + 1);

  const [rnd, setRnd] = useHook();
  console.log('[A] rnd:', rnd);
  setRnd(Math.random());
}

function ComponentB() {
  const [time, setTime] = useHook(Date.now());
  console.log('[B] time:', time);
  setTime(Date.now());
}

// test
load(ComponentA);
load(ComponentA);
load(ComponentA);

load(ComponentB);
load(ComponentB);