[RxJS] Implement RxJS `mergeMap` through inner Observables to Subscribe and Pass Values Through

Understanding sources and subscribers makes it much easier to understand what's going on with mergeMap under the hood. Where a typical operator invokes destination.next directly, mergeMap wraps destination.next inside of a new source/subscriber combo…

[RxJS] Implement RxJS `switchMap` by Canceling Inner Subscriptions as Values are Passed Through

switchMap is mergeMap that checks for an "inner" subscription. If the "inner" subscription exists, switchMap unsubscribes from that "inner" subscription which effectively "cancels" any pending pushes. import { fromE…

[RxJS] Implement RxJS `concatMap` by Waiting for Inner Subscriptions to Complete

Unlike mergeMap and switchMap, concatMap focuses on when "inner" subscriptions "complete" by using a "buffer". Each time concatMap receives a value, it adds each value to a "buffer", waits for previous "inner&q…

[RxJS] Use RxJS mergeMap to map and merge high order observables

Like RxJS switchMap() is a shortcut for map() and switch(), we will see in this lesson how mergeMap() is a shortcut for map() and mergeAll(), and learn its arguments for customised behavior. const clickObservable = Rx.Observable .fromEvent(document,…

[RxJS] Convert RxJS Subjects to Observables

The use of RxJS Subjects is common, but not without problems. In this lesson we will see how they can be usually safely replaced with plain Observables. Check the follow code: const click$ = new Rx.Subject(); document.addEventListener('click', functi…

[RxJS] Use RxJS concatMap to map and concat high order observables

Like switchMap and mergeMap, concatMap is a shortcut for map() followed by a concatAll(). In this lesson we will explore this RxJS operator and its properties. const clickObservable = Rx.Observable .fromEvent(document, 'click'); function performReque…

[Javascript + rxjs] Simple drag and drop with Observables

Armed with the map and concatAll functions, we can create fairly complex interactions in a simple way. We will use Observable to create a simple drag and drop example with basic DOM elements. <!DOCTYPE html> <html> <head lang="en"…

[RxJS] Implement the `map` Operator from Scratch in RxJS

While it's great to use the RxJS built-in operators, it's also important to realize you now have the knowledge to write them by yourself if needed. The mapoperator turns out to be a simple MapSubscriber which takes a function and applies it to the va…

[RxJS] Implement pause and resume feature correctly through RxJS

Eventually you will feel the need for pausing the observation of an Observable and resuming it later. In this lesson we will learn about use cases where pausing is possible, and what to do when pausing is impossible. const resume$ = new Rx.Subject();…

[RxJS] Chain RxJS Operators Together with a Custom `pipe` Function using Array.reduce

Instead of writing complex operators, it's usually best to write simple, single-purpose operators then chain them together when necessary. The pipefunction takes functions as arguments, invokes each function with the value, then passes the returned r…

[RxJS] What RxJS operators are

We have covered the basics of what is Observable.create, and other creation functions. Now lets finally dive into operators, which are the focus of this course. We will see how operators are simple pure functions attached to the Observable type. var…

RxJS速成 (下)

上一部分: http://www.cnblogs.com/cgzl/p/8641738.html Subject Subject比较特殊, 它即是Observable又是Observer. 作为Observable, Subject是比较特殊的, 它可以对多个Observer进行广播, 而普通的Observable只能单播, 它有点像EventEmitters(事件发射器), 维护着多个注册的Listeners. 作为Observable, 你可以去订阅它, 提供一个Observer就会正常的收…

Angular快速学习笔记(4) -- Observable与RxJS

介绍RxJS前,先介绍Observable 可观察对象(Observable) 可观察对象支持在应用中的发布者和订阅者之间传递消息. 可观察对象可以发送多个任意类型的值 -- 字面量.消息.事件. 基本用法和词汇作为发布者,你创建一个 Observable 的实例,其中定义了一个订阅者(subscriber)函数. 当有消费者调用 subscribe() 方法时,这个函数就会执行. 订阅者函数用于定义"如何获取或生成那些要发布的值或消息". 要执行所创建的可观察对象,并开始从中接收通…

rxjs的世界

rxjs学习了几个月了,看了大量的东西,在理解Observable的本文借鉴的是渔夫的故事,原文,知识的主线以<深入浅出rxjs>为主,动图借鉴了rxjs中文社区翻译的文章和国外的一个动图网站正文: 在思维的维度上加入时间考量一.函数响应式编程 Rxjs使用了一种不同于传统的编程模式----函数响应式编程 1.1 函数化编程函数化编程对函数的使用有一些特殊的要求声明式纯函数数据不可变性保持原有数据不变,让新的数据发生变化为什么最近函数式编程崛起从硬件发展角度,函数式编程的性能…

Angular Multiple HTTP Requests with RxJS

原文:https://coryrylan.com/blog/angular-multiple-http-requests-with-rxjs --------------------------------------------------------------- Cory Rylan Nov 15, 2016 Updated Feb 25, 2018 - 5 min readangular rxjs This article has been updated to the latest v…

RxJS 6有哪些新变化？

我们的前端工程由Angular4升级到Angular6,rxjs也要升级到rxjs6. rxjs6的语法做了很大的改动,幸亏引入了rxjs-compact包,否则升级工作会无法按时完成. 按照官方的建议,逐步将原rxjs语法改为rxjs6后,要去掉rxjs-compact包. rxjs-compact包无法转换一些语法,我们的工程中没用到这些特性,原rxjs代码可以转为rxjs6. 原文链接:https://segmentfault.com/a/1190000014956260 RxJs 6于…

RxJS + Redux + React = Amazing!（译二）

今天,我将Youtube上的<RxJS + Redux + React = Amazing!>的后半部分翻译(+机译)了下来,以供国内的同学学习,英文听力好的同学可以直接看原版视频: https://www.youtube.com/watch?v=AslncyG8whg Observable 什么是Observable?让我们快速来了解一下它吧! Observable是一个由零个.一个或多个值组成的流.注意,是零个.一个或多个值.零个意味着可以没有值,这完全没问题.一个值的情况就像是Promi…

RxJS v6 学习指南

为什么要使用 RxJS RxJS 是一套处理异步编程的 API,那么我将从异步讲起. 前端编程中的异步有:事件(event).AJAX.动画(animation).定时器(timer). 异步常见的问题回调地狱(Callback Hell) 竞态条件(Race Condition) 内存泄漏(Memory Leak) 管理复杂状态(Manage Complex States) 错误处理(Exception Handling) 回调地狱就是指层层嵌套的回调函数,造成代码难以理解,并且难以协调组织…

升级到Angular6后对老版本的RXJS代码做相应的调整

还没有了解过RXJS6的童鞋,可以查看我的另外一篇博文,此篇博文主要是对于RXJS5升级到RXJS6的代码调整示例 RXJS5版本在RXJS5上我们是这样写请求的 import 'rxjs/add/observable/of'; import 'rxjs/add/observable/throw'; import 'rxjs/add/observable/map'; import 'rxjs/add/observable/mergemap'; this.http .get<{id: numbe…

[Angular] Upgrading to RxJS v6

This is just a learning blog post, check out the talk. 1. Custom pipeable operators: Custom pipeable operator is just a high order function which return an observable. const pow = (p: number) => (source: Observable<number>) => source.pipe(map(…

[RxJS] Split an RxJS Observable into groups with groupBy

groupBy() is another RxJS operator to create higher order observables. In this lesson we will learn how groupBy works for routing source values into different groups according to a calculated key. const numbersObservable = Rx.Observable.interval(500)…

[RxJS] Groupby operator

The use case is similar to Twitter "like" button, you can click "click" button on different post, each "like" button are isolated, it preforms optimistic UI render, handling the back-press on backend, cancel previous request…

RxJS速成 (上)

What is RxJS? RxJS是ReactiveX编程理念的JavaScript版本.ReactiveX是一种针对异步数据流的编程.简单来说,它将一切数据,包括HTTP请求,DOM事件或者普通数据等包装成流的形式,然后用强大丰富的操作符对流进行处理,使你能以同步编程的方式处理异步数据,并组合不同的操作符来轻松优雅的实现你所需要的功能下面废话不说, 直接切入正题. 准备项目我使用typescript来介绍rxjs. 因为我主要是在angular项目里面用ts. 全局安装typescrip…

rxjs 简单的demo

开发环境是使用 create-react-app 创建的.再使用 $ cnpm install rxjs 来安装即可开始. $ npx create-react-app my-app $ cd my-app $ cnpm install rxjs $ npm start my-app/src/index.js ////////////////////////////////////////////// // demo1:入门 ///////////////////////////////////…

RxJS入门

一.RxJS是什么? 官方文档使用了一句话总结RxJS: Think of RxJS as Lodash for events.那么Lodash主要解决了什么问题?Lodash主要集成了一系列关于数组.对象.字符串等集合操作,极大的方便了对这些集合数据进行衍生.举个简单的例子:求数组偶数元素的平方和 const { pipe, filter, map, reduce } = require('lodash/fp') const source = [0, 1, 2, 3, 4] const res…

RxJS——订阅（Subscription）

订阅(Subscription) 什么是订阅?订阅是一个对象,它表示一个处理完就释放(disposable)的资源,是 Observable 的一个执行程序.订阅有一个很重要的方法,unsubscribe,它是无参的,只是处理订阅的资源.在上个版本的 RxJS,Subscription 又叫 "Disposable". import { interval } from 'rxjs'; const observable = interval(1000); const subscripti…

react programming

So you're curious in learning this new thing called Reactive Programming, particularly its variant comprising of Rx, Bacon.js, RAC, and others. 相信你们在学习响应式编程这个新技术的时候都会充满了好奇,特别是它的一些变体,包括Rx系列.Bacon.js.RAC和其他的一些变体. Learning it is hard, even harder by the…

如何在AngularX 中使用ngrx

ngrx 是 Angular框架的状态容器,提供可预测化的状态管理. 1.首先创建一个可路由访问的模块这里命名为:DemopetModule. 包括文件:demopet.html.demopet.scss.demopet.component.ts.demopet.routes.ts.demopet.module.ts 代码如下: demopet.html  <h1>Demo</h1> demopet.scss h1{ color:#d700…

angular 4 实现的tab栏切换

管理系统 tab 切换页,是一种常见的需求,大概如下: 点击左边菜单,右边显示相应的选项卡,然后不同的选项卡面可以同时编辑,切换时信息不掉失! 用php或.net,java的开发技术,大概是切换显示,然后加一个ifram来做到,或者通过ajax加载信息显示相应的层. 但是如果用angular 要如何实现呢?第一个想法,是否可以用同样的ifarm来实现呢? 第二个想到的是路由插座大概是这样的 <router-outlet name="main-content" (activate)…

ngRx 官方示例分析 - 6 - Effect

@ngrx/effect 前面我们提到,在 Book 的 reducer 中,并没有 Search 这个 Action 的处理,由于它需要发出一个异步的请求,等到请求返回前端,我们需要根据返回的结果来操作 store.所以,真正操作 store 的应该是 Search_Complete 这个 Action.我们在 recducer 已经看到了. 对于 Search 来说,我们需要见到这个 Action 就发出一个异步的请求,等到异步处理完毕,根据返回的结果,构造一个 Search_Complet…

【[RxJS] Implement RxJS `mergeMap` through inner Observables to Subscribe and Pass Values Through】的更多相关文章