vue运用了哪些模式

  function Person (name, age) {
    this.name = name
    this.age = age
    this.info = function () {
      console.log(`我的名字叫${this.name}, 我今年${this.age}了`)
    }
  }
  Person.getInstance = function (name, age) {
    if (!this.instance) {
      this.instance = new Person(name, age)
    }
    console.log(this.instance)
    return this.instance
  }
  let b1 = Person.getInstance('单例1', 18)
  let b2 = Person.getInstance('单例2', 18)
  b1.info()
  b2.info()

 function Factory (name, age) {
   this.name = name;
   this.age = age;
   // 或者
   // let obj = {}
   // obj.name = name
   // obj.age = age
   // return obj
 }
 Factory.prototype.say = function () {
   console.log(`我的名字叫${this.name}, 我今年${this.age}了`)
 }
 let zs = new Factory('张三', 18);
 let ls = new Factory('李四', 20);
 zs.say()
 ls.say()

 function before (fn, callback) {
    let _this = this;
    return function () {
      callback.apply(this, arguments)
      return fn.bind(this, arguments)
    }
  }

  function after (fn, callback) {
    let _this = this 
    return function () {
      let res = fn.apply(this, arguments)
      callback.apply(this, arguments)
      return res
    }
  }
  // before和after是两个高阶函数，让我们一起回忆一下什么是高阶函数？
  // 还知道call，apply,bind的区别吗
  let getName = function getName () {
    // 加入这是你同事写的烂代码，看不下去的那种，那么别动他的代码
    console.log('这是getName函数')
  }

  before(getName, function () {
    // 这个就是你要写的新逻辑
    console.log('切入前代码')
  })()

  after(getName, function () {
    // 这个也是你要写的新逻辑
    console.log('切入后代码')
  })()

 let strategy = {
    'A': function (bonus) {
      return bonus * 4
    },
    'B': function (bonus) {
      return bonus * 3
    }
  }

  function fn (level, bonus) {
    return strategy[level](bonus)
  }

  let result = fn('A', 4000)
  console.log(result, 'result')
  // 策略模式提供了开放-封闭原则，将算法或者方法封装在一个类中，使它们易于切换，易于替换。

  function func (a, b) {
    let f = function f() {
      return a + b
    }
    return f
  }

// 这里可以将所有的表单验证正则函数写在这里
export const loginUsername = (str) => {
  return /^[a-zA-Z0-9_]{3,20}$/.test(str);
};

import * as validateFORM from './validate';
export const gene = (key, msg) => {
  return (r, v, c) => {
    if (validateForm[key](v)) {
      c();
    } else {
      c(new Error(msg));
    }
  };
};

// 这样看着是不是很清晰明了
import {gene} from '@/utils/formValidateGene';
rules: {
     account: [{ required: true, validator: gene('loginUsername', '请输入合适的账号'), trigger: ['blur', 'change'] }]
 }

class Observer {
  client = {}
  // 订阅
  listen (key, fn) {
    if (!this.client[key]) {
      this.client[key] = []
    } 
      this.client[key].push(fn)
  }
  // 发布
  publish (key) {
    this.client[key].forEach(fn => {
      fn.apply(this, arguments)
    })
  }
}

let observer = new Observer()
observer.listen('华为', (model, brand) => {
  console.log(model, brand)
})
observer.listen('苹果', function (model, brand) {
  console.log(model, brand)
})
observer.publish('华为', 'P50')
observer.publish('苹果', '14')

class EventEmitter {
    constructor () {
      this.client = {}
    }
    on (key, fn) {
      if (!this.client[key]) {
        this.client[key] = []
      }
      this.client[key].push(fn)
    }
    trigger (key, ...args) {
      this.client[key].forEach(cb => cb(...args))
    }
  }
  let event = new EventEmitter()
  event.on('hello', function(res) {
    console.log('hello', res)
  })
  
  let data = {
    name: '测试'
  }
  Object.defineProperty(data, 'name', {
    get (val) {
      // console.log(val)
    },
    set (newVal) {
      console.log(newVal)
      event.trigger('hello', newVal)
    }
  })
  data.name = '正在测试'