December 2017
Intermediate to advanced
329 pages
6h 9m
Chinese
Content preview from React学习手册
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174
｜
第
7
章
图
7
-
7
：Facebook的Flux设计模式
在
Flux
中，
Action
和
State
都是不可变数据。
Action
可以来自某个
View
，或者来自其他
源地址，一般是一个
Web
服务器。
每次变更都需要一个
Action
。每个
Action
提供制造变更的一组指令集。
Action
也可以
被当作菜谱，告诉我们变更的内容是什么，创建变更时用到了哪些数据，以及
Action
的源头。用户唯一可以变更的就是
Store
。
Store
更新了数据，
View
在
UI
上渲染这些更
新，而
Action
会告知我们发生变更的过程和原因。
将用户的应用程序的数据流限制在这种设计模式下，将会使应用程序更易于修复和扩
展。来看看图
7-8
中的应用程序。我们会发现每个被分发的
Action
都被记录到控制台
上。这些
Action
告知我们当前
UI
显示大号数字
3
的具体流程。
如你所见，导致最后一次
State
变更的是一个
TICK
。它将之前的计数值修改为现在的
计数值
3
，看上去之前的计数值应该是
4
。这些
Action
告诉我们
State
的变化过程。我们
可以按图索骥，向上追溯到源头发现首次变更的计数值是
9
，因此该程序大概是一个
从
10
开始的倒计时程序。
来看看这个倒计时应用程序是如何使用
Flux
设计模式构建的。我们将会介绍设计模式
的每个部分，并讨论它们对倒计时应用中单向数据流的贡献。
View
让我们先从
View
开始，即一个
React
无状态组件。
Flux
将会管理应用程序的
State
，因
此除非用户需要使用一个生命周期函数，否则将不会用到类组件。
倒计时应用的
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.