While merge is an OR-style combination operator, combineLatest is an AND-style combination operator. This lesson explains what AND-style combination means, and how you can join values from two or more Observables in a formula. At the begin, there is…

Operator combineLatest is not the only AND-style combinator. In this lesson we will explore withLatestFrom, another AND-style combination operator, and how it works essentially as map() operator, with some combination properties. var foo = Rx.Observa…

CombineLatest and withLatestFrom are both AND-style combination operators. In this lesson, we will learn about zip, our last AND-style combinator. It uses the n-th value of each member Observable to produce the n-th output value. If you zip two obser…

This lesson will teach you about another horizontal combination operator: buffer and its variants. Buffer groups consecutive values together, emitting the output as an array. The buffer variants and their arguments allow to specify when to close the…

All of the combination operators take two or more observables as input. These operators may also be alternatively called "vertical combination operators", because of how they work in a marble diagram. Next, we will learn about scan(), which is a…

rxjs自定义operator…

We just saw map which is a transformation operator. There are a couple of categories of operators, such as filtering, combination, flattening, etc. One of these categories is the utility operators. The most important utility operator is do, useful fo…

RxJS is a lot about the so-called "operators". We will learn most of the important operators, one by one. In this lesson, we will see our first creation operator: of(). var foo = Rx.Observable.of(42, 100, 200); // var bar = Rx.Observable.create(…

We have seen how Subjects are useful for sharing an execution of an RxJS observable to multiple observers. However, this technique requires some laborious setting up. In this lesson we will learn about the multicast() operator which helps solve the s…

Operator repeat() is somewhat similar to retry(), but is not for handling operators. In this lesson we learn how repeat works. var foo = Rx.Observable.interval(500) .zip(Rx.Observable.of('a','b','c','d'), (x,y)=>y); var bar = foo.map(x => x.toUpperC…

Some Observables may complete, and we may want to append another Observable to the one which just completed. This lesson teaches you how to use the concat() operator for either appending or prepending, and how the shortcut operator startWith() is an…

This lesson introduces filter: an operator that allows us to let only certain events pass, while ignoring others. var foo = Rx.Observable.interval(1000); /* --0--1--2--3--4--5--6--7- filter(x => x % 2 === 0) --0-----2-----4-----6---- */ var bar = foo…

We made our first operator called multiplyBy, which looks a bit useful, but in practice we don't need it because it's too specific: it only does simple multiplication on numbers. In this lesson we will see how the map() operator is useful for any cal…

We have been using Observable.create() a lot in previous lessons, so let's take a closer look how does it work. The create function: var foo = Rx.Observable.create( function(observer){ observer.next(); observer.next(); observer.next(); observer.compl…

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…

Single, race both get only one emit value from the stream. Single(fn): const source = Rx.Observable.from([1,2,3,4,5]); var single = source.single( x => x === 3); /* (12345)| (source) single( x => x === 3) 3| (single) */ race(...observable): Observab…

bufferToggle(open: Observable, () => close: Observalbe : Observalbe<T[]>) bufferToggle take two args, first is opening observable, seconde is a function which return an observable for closing. The closeing observalbe only execute after opening em…

介绍 RxJS是一个异步编程的库,同时它通过observable序列来实现基于事件的编程.它提供了一个核心的类型:Observable,几个辅助类型(Observer,Schedulers,Subjects),受到Array的扩展操作(map,filter,reduce,every等等)启发,允许直接处理异步事件的集合. ReactiveX结合了Observer模式.Iterator模式和函数式编程和集合来构建一个管理事件序列的理想方式. 在RxJS中管理异步事件的基本概念如下: Observa…

rxjs的引入 // 如果以这种方式导入rxjs,那么整个库都会导入,我们一般不可能在项目中运用到rxjs的所有功能 const Rx = require('rxjs'); 解决这个问题,可以使用深链deep link的方式,只导入用的上的功能 import {Observable} from 'rxjs/Observable'; 这样可以减少不必要的依赖,不光可以优化打包文件的大小,还有利于代码的稳定性 另外目前最新的一种解决方案就是Tree Shaking, Tree Shaking只对im…

RxJS 博大精深,看了好几篇文章都没有明白. 范围牵扯到了函数响应式开发去了... 我对函数式一知半解, 响应式更是第一次听到... 唉...不过日子还是得过...混着过先呗 我目前所理解的很浅, 大致上是这样的概念. 1.某些场景下它比promise好用, 它善于过滤掉不关心的东西. 2.它是观察者模式 + 迭代器模式组成的 3.跟时间,事件, 变量有密切关系 4.世界上有一种东西叫 "流" stream, 一个流能表示了一段时间里,一样东西发生的变化. 比如有一个值, 它在某段时…

The scan operator in RxJS is the main key to managing values and states in your stream. Scan behaves just as a reduce function would, but scan is able to collect values from streams over time. This lesson covers using startWith to set the initial acc…

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…

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…

Subscription是什么? 当subscribe一个observable的时候, 返回的就是一个subscription. 它是一个一次性对象(disposable), 它有一个非常重要的方法 ubsubscribe(), 它没有参数, 它会dispose掉subscription所持有的资源, 或者叫取消observable的执行. 第一个例子: import { Observable } from "rxjs/Observable"; import { Subscriptio…

我使用 angular-cli 来搭建项目. ng new infinite-scroller-poc --style=scss 项目生成好后,进入 infinite-scroller-poc 目录下. Angular CLI 提供了一堆命令用来生成组件.指令.服务和模块. 我们来生成一个服务和一个指令. ng g service hacker-news ng g directive infinite-scroller 注意: Angular CLI 会自动在 app.module.ts 里注册…

Install: npm install — save-dev jasmine-marbles Basic example: import {cold, getTestScheduler} from 'jasmine-marbles'; import 'rxjs/add/operator/concat'; describe('Test', () => { it('concat', () => { const one$ = cold('x-x|'); const two$ = cold('-y|…

With the shareReplay operator in place, we would no longer fall into the situation where we have accidental multiple HTTP requests. And this covers the main use cases for doing the most typical read and modification operations, that we would implemen…

RxJs 中创建操作符是创建数据流的起点,这些操作符可以凭空创建一个流或者是根据其它数据形式创建一个流. Observable的构造函数可以直接创建一个数据流,比如: const $source=new Observable(observer=>{ observer.next(1); observer.next(2); observer.next(3); }) 但是在真正的使用过程中很少使用这种方式去创建,RxJx 提供了大量的创建操作符供我们在开发中去使用.创建型操作符打不风都是静态操作符.…

You can load resource based on the url using the a combination of ActivatedRouteand Angular 2’s Http service. Since the params and Http are both streams, you can use RxJS to get the data off the param then switchMap over to an Http request using that…

上一篇:Angular2入门系列教程5-路由(一)-使用简单的路由并在在路由中传递参数 之前介绍了简单的路由以及传参,这篇文章我们将要学习复杂一些的路由以及传递其他附加参数.一个好的路由系统可以使我们的程序更好的工作. 假设你已经跟上了我们的进度. 我们来为我们的文章明细新增一个评论框:当我们在明细中点击评论的时候,在我们的明细页面显示评论,这里,我们就可以完全把明细页面看成一个独立的路由,可以建立自己的子路由页面,做一些评论,分享等操作. 那,首先在data目录下建立我们的评论实体Commen…