74 lines
1.9 KiB
Markdown
74 lines
1.9 KiB
Markdown
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---
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id: 5a24c314108439a4d4036159
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title: Use the Spread Operator on Arrays
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challengeType: 6
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isRequired: false
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videoUrl: ''
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localeTitle: ''
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---
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## Description
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undefined
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## Instructions
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undefined
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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: ''
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testString: 'assert((function() { const initialState = store.getState(); return ( Array.isArray(initialState) === true && initialState[0] === "Do not mutate state!"); })(), "The Redux store should exist and initialize with a state equal to <code>[Do not mutate state!]</code>.");'
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- text: ''
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testString: 'assert(typeof addToDo === "function" && typeof immutableReducer === "function", "<code>addToDo</code> and <code>immutableReducer</code> both should be functions.");'
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- text: ''
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testString: 'assert((function() { const initialState = store.getState(); const isFrozen = DeepFreeze(initialState); store.dispatch(addToDo("__TEST__TO__DO__")); const finalState = store.getState(); const expectedState = [ "Do not mutate state!", "__TEST__TO__DO__" ]; return( isFrozen && DeepEqual(finalState, expectedState)); })(), "Dispatching an action of type <code>ADD_TO_DO</code> on the Redux store should add a <code>todo</code> item and should NOT mutate state.");'
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- text: ''
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testString: 'getUserInput => assert(getUserInput("index").includes("...state"), "The spread operator should be used to return new 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 immutableReducer = (state = ['Do not mutate state!'], action) => {
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switch(action.type) {
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case 'ADD_TO_DO':
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// don't mutate state here or the tests will fail
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return
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default:
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return state;
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}
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};
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const addToDo = (todo) => {
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return {
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type: 'ADD_TO_DO',
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todo
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}
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}
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const store = Redux.createStore(immutableReducer);
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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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// solution required
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```
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</section>
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