Rxjs的使用

1 订阅

通过订阅
import {  Observable } from 'rxjs'
 getRxjsData(){
    return new Observable((observer)=>{
      setTimeout(()=>{
        var username:string='张三'
        observer.next(username)
        //通过next触发  相对于promise重的resolve
      },2000)
    })
  }
  使用时，引入该函数所在的服务或其他
import { RequestService } from '../../service/request.service'
  constructor(public request:RequestService) {
    let rxjsdata  = this.request.getRxjsData();
    rxjsdata.subscribe((data)=>{
    //通过订阅方法
      console.log(data);
    })
}

2 订阅的取消

  constructor(public request:RequestService) {
    let rxjsdata  = this.request.getRxjsData();
    let d = rxjsdata.subscribe((data)=>{
    //通过订阅方法
      console.log(data);
    })
    setTimeout(()=>{
      d.unsubscribe(); /* 取消订阅，可以撤回*/
    },1000)
}
事件将不会触发

3 订阅的多次执行

 getRxjsIntervalData(){
     let count:number = 0
     return new Observable<any>((observable)=>{
       setInterval(()=>{
         count++
         let username = '张三--rxjs--intetval'+" "+count
         observable.next(username)
       },2000)
     })
  }





  let streemInterval = this.request.getRxjsIntervalData()
      streemInterval.subscribe((dataa=>{
        console.log(dataa);

      }))