观察者模式

  • 定义对象间一种一对多的依赖关系，当一个对象改变状态，则所有依赖于它的对象都会得到通知并自动更新
  • 场景: vue的响应式

代码实现

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class Observer {
    states: string[] = []
    update(state: string) {
        this.states.push(state)
    }
}
 
class People {
   state: string = ''
   observer：Observer
   setState(newState:string){
       if(this.state !== newState){
           this.state = newState
           this.notify(this.state)
       }
   } 
   notify(state: string){
       if(this.observer !== null){
           this.observer.update(state)
       }
   }
   setObserver(observer: Observer) {
       this.observer = observer
   }
}
 
const observer = new Observer()
const people = new People().setObserver(observer)
people.setState('shit')
console.log(observer.state)

参考链接