December 2017
Intermediate to advanced
329 pages
6h 9m
Chinese
Content preview from React学习手册
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94
｜
第
5
章
图
5
-
3
：React开发者工具中虚拟DOM的状态
这里可以看到我们的
Menu
组件及其子元素。数据数组中包含两个菜谱对象，我们有两
个
Recipe
元素。每个
Recipe
元素的属性包括菜谱名称、食材成分和烹饪步骤。
虚拟
DOM
是基于应用程序的
State
数据构造的，该数据会作为属性传递给
Menu
组件。
如果我们希望修改数组
recipes
并重绘
Menu
组件，
React
将会以尽可能高效的方式修改
这个
DOM
。
Babel
的
presets
模块
Babel 6
中的
presets
模块中的转译机制有重大变化。它需要工程师显式声明转译
过程中采用哪些模块。其目的是为了让程序更加模块化，同时允许开发人员决定
哪些语法应该被转译。插件可以分为几个类别，所有这些都可以根据应用程序的
需要进行选择。用户根据偏好选择即可：
babel-preset-es2015
将
ES2015
或者
ES6
转译成
ES5
。
babel-preset-es2016
将
ES2016
转译成
ES2015
。
babel-preset-es2017
将属于
ES2017
规范的特性转译成
ES2017
。
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