javascript观察者模式实现自动刷新效果

本文实例为大家分享了js观察者模式实现自动刷新的具体代码，供大家参考，具体内容如下

// author [e-mail]

const observable = obj => {
  const observers = symbol();
  const set = function(target, key, value) {
    const result = reflect.set(target, key, value);
    //console.log("set key:" + key);
    if ( target[observers].has(key) ) {
      target[observers].get(key).foreach(observer => observer());
    }

    return result;
  }

  const get = function(target, key) {
    const result = reflect.get(target, key);
    //console.log("get key:" + key);
    if (arguments.callee.caller) {
      if (!target[observers].has(key)) {
        target[observers].set(key, new set())
      }
      target[observers].get(key).add(arguments.callee.caller);
    }

    return result;
  }

  obj[observers] = new map(); // string => set()
  return new proxy(obj, {set, get});
};

const autorun = fn => fn();

var person = observable({
  firstname: 'matt',
  lastname: 'ruby',
  age: 18,
  weight: 50
});

autorun(function () {
  console.log('autorun.getage: ' + person.firstname + ' ' + person.age);
});

autorun(function () {
  console.log('autorun.getname: ' + person.firstname + ' ' + person.lastname);
});

person.age = 19;
person.weight = 55;
person.firstname = 'test';
person.lastname = 'mylast';
console.log(person.lastname);
person.age = 20;

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。