javascript随笔---简单的get，set实现

亦凉 2022-04-10 14:11 78阅读 0赞

// 第一种
    var obj = {
      name: "111",
      get: function(key) {
        return this[key];
      },
      set: function(key, value) {
        this[key] = value;
      }
    };
    
    console.log(obj.get("name"));
    obj.set("name", "222");
    console.log(obj.get("name"));
    
    // 第二种
    function Account() {
      let name = "111";
    
      function get(key) {
        return this[key];
      }
    
      function set(key, value) {
        this[key] = value;
      }
    
      return {
        name,
        get,
        set
      };
    }
    
    const account = Account();
    console.log(account.get("name"));
    account.set("name", "222");
    console.log(account.get("name"));
    
    // 第三种
    function Person(age) {
      this.age = age;
    }
    Person.prototype.getAge = function() {
      return this.age;
    };
    Person.prototype.setAge = function(newAge) {
      this.age = newAge;
    };
    function Employee(name) {
      this.name = name;
    }
    Employee.prototype = new Person(18);
    Employee.prototype.get = function(key) {
      return this[key];
    };
    Employee.prototype.set = function(key, value) {
      this[key] = value;
    };
    
    const employee = new Employee("111");
    console.log(employee.get("name"));
    employee.set("name", "222");
    console.log(employee.get("name"));
    // delete employee.name;
    // console.log(employee.get("name"));
    console.log(employee.getAge());
    employee.setAge(21);
    console.log(employee.getAge());
    
    const employee2 = new Employee("333");
    console.log(employee2.getAge());
    console.log(employee.getAge());
    console.log(employee2.get("name"));
    console.log(employee.get("name"));
    
    // 第四种
    var o = {
        a: 1,
        b: 2
    }
    var data = {}
    for (const key in o) {
        Object.defineProperty(data, key, {
            get: function () {
                console.log('get');
                return o[key]
            },
            set: function (val) {
                console.log('set');
                o[key] = val
            }
        })
    }
    console.log(data.a);
    data.a = 0
    console.log(data.a);
    // 这里把data和o值绑定，data改变o就改变
    // 不能直接在o上定义属性，因为调用get如果返回o.a那么就会死循环，所以要有一个中转站。