const user = {
  name: 'Alice',
  age: 25
};
<p>const handler = {
get(target, prop) {
console.log(<code>读取属性: ${prop}</code>);
return target[prop];
},
set(target, prop, value) {
console.log(<code>设置属性: ${prop} = ${value}</code>);
if (prop === 'age' && typeof value !== 'number') {
throw new Error('年龄必须是数字');
}
target[prop] = value;
return true;
}
};</p><p>const proxyUser = new Proxy(user, handler);</p><p>proxyUser.name;        // 输出：读取属性: name
proxyUser.age = 30;    // 输出：设置属性: age = 30</p>

function createValidator(target, validators) {
  return new Proxy(target, {
    set(target, prop, value) {
      if (validators[prop] && !validators[prop](value)) {
        console.error(`${prop} 的值 ${value} 不符合验证规则`);
        return false;
      }
      target[prop] = value;
      return true;
    }
  });
}
<p>const person = {};</p><p>const validatedPerson = createValidator(person, {
email: v => typeof v === 'string' && v.includes('@'),
age: v => typeof v === 'number' && v >= 0 && v <= 150
});</p><p>validatedPerson.email = 'alice@example.com';  // 成功
validatedPerson.age = 25;                     // 成功
validatedPerson.age = -5;                     // 失败，输出错误信息</p>

function createInterceptor(func) {
  return new Proxy(func, {
    apply(target, thisArg, args) {
      console.log(`调用函数 ${target.name}，参数:`, args);
      const start = performance.now();
      const result = target.apply(thisArg, args);
      const end = performance.now();
      console.log(`执行耗时: ${end - start}ms`);
      return result;
    }
  });
}
<p>const calculateSum = createInterceptor(function sum(a, b) {
return a + b;
});</p><p>calculateSum(2, 3);<br />
// 输出：
// 调用函数 sum，参数: [2, 3]
// 执行耗时: 0.1ms</p>