zoukankan      html  css  js  c++  java
  • [RxJS] AsyncSubject: representing a computation that yields a final value

    This lesson will teach you about AsyncSubject, another type of Subject with some replaying logic inside. We will also look at some use cases for this peculiar RxJS subject variant.

    AsyncSubject:

    Emit last value only when sequence completed. 

    BehaviorSubject:

    Replay onces, only before compleation.

    ReplaySubject:

    Replay many, before of after compleation.

    var subject = new Rx.AsyncSubject();
    
    // Subject
    // ReplaySubject: replays many, before or after completion
    // BehaviorSubject: replays one, only before completion
    // AsyncSubject: replays one, only if completed
    
    var observerA = {
      next: function (x) { console.log('A next ' + x); },
      error: function (err) { console.log('A error ' + err); },
      complete: function () { console.log('A done'); },
    };
    
    subject.subscribe(observerA);
    console.log('observerA subscribed');
    
    var observerB = {
      next: function (x) { console.log('B next ' + x); },
      error: function (err) { console.log('B error ' + err); },
      complete: function () { console.log('B done'); },
    };
    
    setTimeout(() => subject.next(1), 100);
    setTimeout(() => subject.next(2), 200);
    setTimeout(() => subject.next(3), 300);
    setTimeout(() => subject.complete(), 350);
    
    /*
    ----1---2---3--|       
      .............3|
                       3|
    */
    
    setTimeout(function () {
      subject.subscribe(observerB);
      console.log('observerB subscribed');
    }, 400);
    /*
    "observerA subscribed"
    "A next 3"
    "A done"
    "B next 3"
    "B done"
    "observerB subscribed"
    */
  • 相关阅读:
    MyBatis的几种使用形式。
    laradock开发环境搭建笔记
    前端如何引入vConsole
    技术更迭,一往无前
    博客园使用markdown
    python telnetlib 模块实现功能端口扫描
    kubernetes之ingress部署
    kubernetes之ingress error: endpoints "default-http-backend" not found
    mvc 查询条件回显
    BootStrap 下来菜单点击两次才弹框问题
  • 原文地址:https://www.cnblogs.com/Answer1215/p/5977464.html
Copyright © 2011-2022 走看看