79d9012432
* fix(curriculum): tests quotes * fix(curriculum): fill seed-teardown * fix(curriculum): fix tests and remove unneeded seed-teardown
76 lines
2.9 KiB
Markdown
76 lines
2.9 KiB
Markdown
---
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id: 5a24c314108439a4d403614b
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title: Create a Redux Store
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challengeType: 6
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isRequired: false
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---
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## Description
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<section id='description'>
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Redux is a state management framework that can be used with a number of different web technologies, including React.
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In Redux, there is a single state object that's responsible for the entire state of your application. This means if you had a React app with ten components, and each component had its own local state, the entire state of your app would be defined by a single state object housed in the Redux <code>store</code>. This is the first important principle to understand when learning Redux: the Redux store is the single source of truth when it comes to application state.
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This also means that any time any piece of your app wants to update state, it <strong>must</strong> do so through the Redux store. The unidirectional data flow makes it easier to track state management in your app.
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</section>
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## Instructions
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<section id='instructions'>
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The Redux <code>store</code> is an object which holds and manages application <code>state</code>. There is a method called <code>createStore()</code> on the Redux object, which you use to create the Redux <code>store</code>. This method takes a <code>reducer</code> function as a required argument. The <code>reducer</code> function is covered in a later challenge, and is already defined for you in the code editor. It simply takes <code>state</code> as an argument and returns <code>state</code>.
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Declare a <code>store</code> variable and assign it to the <code>createStore()</code> method, passing in the <code>reducer</code> as an argument.
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<strong>Note:</strong> The code in the editor uses ES6 default argument syntax to initialize this state to hold a value of <code>5</code>. If you're not familiar with default arguments, you can refer to the <a target="_blank" href="https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/es6/set-default-parameters-for-your-functions">ES6 section in the Curriculum</a> which covers this topic.
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: The redux store exists.
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testString: assert(typeof store.getState === 'function', 'The redux store exists.');
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- text: The redux store has a value of 5 for the state.
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testString: assert(store.getState()=== 5, 'The redux store has a value of 5 for the state.');
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='jsx-seed'>
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```jsx
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const reducer = (state = 5) => {
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return state;
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}
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// Redux methods are available from a Redux object
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// For example: Redux.createStore()
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// Define the store here:
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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const reducer = (state = 5) => {
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return state;
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}
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// Redux methods are available from a Redux object
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// For example: Redux.createStore()
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// Define the store here:
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const store = Redux.createStore(reducer);
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```
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</section>
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