【JS proxy 】

对象 proxy

      const hh = { name:"zhangsan", age: 18 };
      const proxy = new Proxy(hh, {
        get(target, key) {
          if (key in target) {
            return target[key];
          } else {
            return "没有这个属性";
          }
        },
        set(target, key, value) {
          if (key in target) {
            target[key] = value;
          } else {
            return "没有这个属性";
          }
          return true;
      },
    });
    console.log(proxy.name);

函数 proxy

 // 函数 proxy
    function factorial(n) {
      return n === 1 ? 1 : n * factorial(n - 1);
    }
    let proxy = new Proxy(factorial, {
      apply(func, obj, args) {
        console.time("start");
        func.apply(this, args);
        console.timeEnd("start");
      },
    });
    proxy(5);

数组

let arr = [1, 2, 3];
let proxy = new Proxy(arr, {
  get(target, key, receiver) {
  // 很容易玩坏
  return target[key];
  },
});
console.log(proxy[0]);