blocks|key|651538|text|当你做的时候|type|unstyled|depth|inlineStyleRanges|entityRanges|data|651539|import+<something>+from+'somePath'|code-block|syntax|javascript|651540|somePath通常是指向文件或node_modules中的模块的相对路径，但它也可以是指向包含index.js文件的文件夹的路径。|offset|length|style|CODE|651541|在这里，同一个目录中有一个名为reducers的文件夹，该文件夹包含一个index.js文件，该文件可以：|651542|export+default+combineReducers({+todos,+visibilityFilter+});|651543|因此，import+rootReducer+from+"./reducers";指向嵌套文件夹中的index.js文件，并将其默认导出放到rootReducer变量中。|651544|这并不是针对React或Redux的--这对于import语法在JavaScript中是通用的。|651545|例如，如果app.js包含import+something+from+'./components'，下面的两个文件系统结构将导致路径解析成功：|651546|%7C-+app.js
%7C-+components+(folder)
+++%7C+index.js
+++%7C+componentA.js
+++%7C+componentB.js|651547|%7C-+app.js
%7C-+components.js|651548|entityMap^0|0|0|0|8|G|C|1C|8|0|F|8|10|8|0|0|3|11|1D|8|1X|B|0|N|6|0|5|6|D|10|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|14|8|@$I|15|J|16|K|L]|$I|17|J|18|K|L]|$I|19|J|1A|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|1B|8|@$I|1C|J|1D|K|L]|$I|1E|J|1F|K|L]]|9|@]|A|$]]|$1|O|3|P|5|D|7|1G|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|1H|8|@$I|1I|J|1J|K|L]|$I|1K|J|1L|K|L]|$I|1M|J|1N|K|L]]|9|@]|A|$]]|$1|S|3|T|5|6|7|1O|8|@$I|1P|J|1Q|K|L]]|9|@]|A|$]]|$1|U|3|V|5|6|7|1R|8|@$I|1S|J|1T|K|L]|$I|1U|J|1V|K|L]]|9|@]|A|$]]|$1|W|3|X|5|D|7|1W|8|@]|9|@]|A|$E|F]]|$1|Y|3|Z|5|D|7|1X|8|@]|9|@]|A|$E|F]]|$1|10|3|-4|5|6|7|1Y|8|@]|9|@]|A|$]]]|11|$]]

When you do
<pre><code>import &lt;something&gt; from 'somePath'
</code></pre>
<code>somePath</code> is usually a relative path to a file, or to a module in <code>node_modules</code>, but it can also be a path to a folder which contains an <code>index.js</code> file.
Here, there's a folder named <code>reducers</code> in the same directory, and that folder contains an <code>index.js</code> file which does:
<pre><code>export default combineReducers({ todos, visibilityFilter });
</code></pre>
So <code>import rootReducer from &quot;./reducers&quot;;</code> points to that <code>index.js</code> file in the nested folder, and puts its default export into the <code>rootReducer</code> variable.
This is not specific to React or Redux - this is universal for <code>import</code> syntax in JavaScript.
For example, if <code>app.js</code> contains <code>import something from './components'</code>, both file system structures below will result in the path resolving successfully:
<pre class="lang-none prettyprint-override"><code>|- app.js
|- components (folder)
 | index.js
 | componentA.js
 | componentB.js
</code></pre>
<pre class="lang-none prettyprint-override"><code>|- app.js
|- components.js
</code></pre>

blocks|key|1376892|text|答案很简单：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1376893|import+rootReducer+from+"./reducers";|code-block|syntax|javascript|1376894|将自动在reducers-folder中查找一个名为index.EXTENSION的文件。|offset|length|style|CODE|1376895|如果您查看src/reduc/reducers/index.js，您将看到如下所示：|1376896|export+default+combineReducers({+todos,+visibilityFilter+});|1376897|它实际上是导出示例项目在src/redux/store.js中导入的内容。|1376898|entityMap^0|0|0|4|8|0|5|R|0|0|C|I|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@$I|10|J|11|K|L]]|9|@]|A|$]]|$1|O|3|P|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|13|8|@$I|14|J|15|K|L]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|16|8|@]|9|@]|A|$]]]|T|$]]

The answer is simple:
<pre class="lang-js prettyprint-override"><code>import rootReducer from &quot;./reducers&quot;;
</code></pre>
will automatically look inside the <code>reducers</code>-folder for an file called index.EXTENSION.
If you look into <code>src/reduc/reducers/index.js</code> you will see the following like:
<pre class="lang-js prettyprint-override"><code>export default combineReducers({ todos, visibilityFilter });
</code></pre>
which is actually exporting what the example-project is importing in <code>src/redux/store.js</code>.

I am studying react-redux using the official guide:
<a href="https://react-redux.js.org/introduction/basic-tutorial" rel="nofollow noreferrer">https://react-redux.js.org/introduction/basic-tutorial</a>
In this guide there is the link to the example project:
<a href="https://codesandbox.io/s/9on71rvnyo" rel="nofollow noreferrer">https://codesandbox.io/s/9on71rvnyo</a>
In this example there is a part that I am unable to understand how could work.
The issue (i.e the part that I am unable to understand) is in the file src/redux/store.js
In this file there is an import statement:
<pre><code>import rootReducer from &quot;./reducers&quot;;
</code></pre>
but in the directory tree there is no rootReducer defined and exported in any of the file in the whole project.
How can the app ever work?
What am I missing?

React- redux online example should not work

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在使用官方指南学习redux：在本指南中，有指向示例项目的链接：在这个例子中，有一个部分我无法理解如何工作。问题(即我无法理解的部分)出现在文件src/redux/store.js中。在这个文件中有一个import语句：import rootReducer from "./reducers";但是在目录树中，在整个...

问在线示例不起作用
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