RxSwift 系列(三) -- Combination Operators 前言 本篇文章将要学习如何将多个Observables组合成一个Observable. Combination Operators在RxSwift中的实现有五种: startWith merge zip combineLatest switchLatest startWith 在Observable释放元素之前,发射指定的元素序列.更多详情 上面这句话是什么意思呢?翻译成大白话就是在发送一个东西之前,我先发送一个我指定…

1. Observable与观察者模式的关系 其实这里讲的Observable就是一种观察者模式,只不过RxJS把Observable结合了迭代模式以及附件了很多的operator,让他变得很强大,也增添了一些神秘的色彩. 那么设计模式中的观察者模式,其实是非常简单的,可以用生活中的订牛奶的示例来说明, 你订阅了某订奶机构的牛奶,那么付了钱之后,在预定的时间内都会给你送牛奶,如果你取消订阅,那么第二天就收不到新鲜的牛奶了. 其实,观察者模式的模型在生活中很多,突然想到订牛奶,是因为我前段时间订牛…

It is quite common to need an Observable that ticks periodically, for instance every second or every 100 miliseconds. We will learn about operators interval() and timer(), both of which are similar to setInterval() in JavaScript. Interval(period): Yo…

This lesson introduces operators empty(), never(), and throw(), which despite being plain and void of functionality, are very useful when combining with other Observables. empty: var foo = Rx.Observable.empty(); // the same as var foo = Rx.Observable…

Besides converting arrays and promises to Observables, we can also convert other structures to Observables. This lesson teaches how we can convert any addEventHandler/removeEventHandler API to Observables.  fromEvent(target, EventType): var foo = Rx.…

The of() operator essentially converted a list of arguments to an Observable. Since arrays are often how we structure list of things in JavaScript, we should have a way of transforming arrays into Observables. This lesson teaches how you can convert…

Get a better understanding of the RxJS Observable by implementing one that's similar from the ground up. class SafeObserver { constructor(destination) { this.destination = destination; } next(value) { const destination = this.destination; if (destina…

Sometimes, the helper methods that RxJS ships with such as fromEvent, fromPromise etc don't always provide the exact values you want & you end up having to do extra work to force them into the shape you require. For more fine-grained control you can…

old import { Injectable } from '@angular/core'; import { BehaviorSubject } from 'rxjs'; @Injectable({ providedIn: 'root' }) export class DataService { private dataSource = new BehaviorSubject(Object); public currentData = this.dataSource.asObservable…

前言 本篇文章将要学习RxSwift中四种转换操作符: map flatMap flatMapLatest scan map 通过使用一个闭包函数将原来的Observable序列转换为一个新的Observable序列. let disposeBag = DisposeBag() Observable.of(1,2,3).map({return 10 * $0}).subscribe({print($0)}).disposed(by: disposeBag) 打印结果: next(10) next…