怎样利用Proxy和Reflect实现自动化的依赖追踪？

let activeEffect = null;

// 依赖存储结构：按对象和键名组织
const targetMap = new WeakMap();

function track(target, key) {
  if (!activeEffect) return;
  let depsMap = targetMap.get(target);
  if (!depsMap) {
    depsMap = new Map();
    targetMap.set(target, depsMap);
  }
  let dep = depsMap.get(key);
  if (!dep) {
    dep = new Set();
    depsMap.set(key, dep);
  }
  dep.add(activeEffect);
}

function trigger(target, key) {
  const depsMap = targetMap.get(target);
  if (!depsMap) return;
  const dep = depsMap.get(key);
  if (dep) {
    dep.forEach(effect => effect());
  }
}

function reactive(target) {
  return new Proxy(target, {
    get(target, key, receiver) {
      const result = Reflect.get(target, key, receiver);
      track(target, key); // 收集依赖
      return result;
    },
    set(target, key, value, receiver) {
      const result = Reflect.set(target, key, value, receiver);
      trigger(target, key); // 触发更新
      return result;
    }
  });
}

function effect(fn) {
  activeEffect = fn;
  fn(); // 执行时触发 getter，自动收集依赖
  activeEffect = null;
}

const state = reactive({
  count: 0
});

effect(() => {
  console.log('count is:', state.count);
});

state.count++; // 控制台输出：count is: 1