浅析Vue为什么需要同时使用Ref和Reactive

const userInfo = {
  firstName: "fotis",
  age: 35,
};
const handler = {
  get(target, property) {
    if (property === "firstName") {
      const name = target[property]
      return name.charAt(0).toUpperCase() + name.slice(1);
    }
    if (property === "age") {
      return '--'
    }
    return target[property]
  },
};
const proxy = new Proxy(userInfo, handler);
console.log(proxy.firstName) // "Fotis"
console.log(proxy.age) // "--"

const userInfo = {
  firstName: "Fotis",
  age: 35,
};
const handler = {
  set(target, prop, value) {
    if (prop === "age") {
      if (!Number.isInteger(value)) {
        throw new TypeError("The age is not an integer");
      }
      if (value > 200) {
        throw new RangeError("The age seems invalid");
      }
    }
    target[prop] = value;
    return true;
  },
};
const proxy = new Proxy(userInfo, handler);
proxy.age = 12 // OK
proxy.age = 300 // Error: The age seems invalid

function reactive(obj) {
  return new Proxy(obj, {
    get(target, key) {
      track(target, key)
      return target[key]
    },
    set(target, key, value) {
      target[key] = value
      trigger(target, key)
    }
  })
}

function ref(value) {
  const refObject = {
    get value() {
      track(refObject, 'value')
      return value
    },
    set value(newValue) {
      value = newValue
      trigger(refObject, 'value')
    }
  }
  return refObject
}