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---
id: 5a24c314108439a4d403615a
title: Remove an Item from an Array
challengeType: 6
isRequired: false
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forumTopicId: 301447
2018-09-30 22:01:58 +00:00
---
## Description
< section id = 'description' >
Time to practice removing items from an array. The spread operator can be used here as well. Other useful JavaScript methods include < code > slice()< / code > and < code > concat()< / code > .
< / section >
## Instructions
< section id = 'instructions' >
The reducer and action creator were modified to remove an item from an array based on the index of the item. Finish writing the reducer so a new state array is returned with the item at the specific index removed.
< / section >
## Tests
< section id = 'tests' >
```yml
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tests:
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- text: The Redux store should exist and initialize with a state equal to < code > [0,1,2,3,4,5]</ code >
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testString: assert((function() { const initialState = store.getState(); return (Array.isArray(initialState) === true & & DeepEqual(initialState, [0, 1, 2, 3, 4, 5])); })());
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- text: < code > removeItem</ code > and < code > immutableReducer</ code > both should be functions.
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testString: assert(typeof removeItem === 'function' & & typeof immutableReducer === 'function');
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- text: Dispatching the < code > removeItem</ code > action creator should remove items from the state and should NOT mutate state.
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testString: assert((function() { const initialState = store.getState(); const isFrozen = DeepFreeze(initialState); store.dispatch(removeItem(3)); const state_1 = store.getState(); store.dispatch(removeItem(2)); const state_2 = store.getState(); store.dispatch(removeItem(0)); store.dispatch(removeItem(0)); store.dispatch(removeItem(0)); const state_3 = store.getState(); return isFrozen & & DeepEqual(state_1, [0, 1, 2, 4, 5]) & & DeepEqual(state_2, [0, 1, 4, 5]) & & DeepEqual(state_3, [5]); })());
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```
< / section >
## Challenge Seed
< section id = 'challengeSeed' >
< div id = 'jsx-seed' >
```jsx
const immutableReducer = (state = [0,1,2,3,4,5], action) => {
switch(action.type) {
case 'REMOVE_ITEM':
// don't mutate state here or the tests will fail
return
default:
return state;
}
};
const removeItem = (index) => {
return {
type: 'REMOVE_ITEM',
index
}
}
const store = Redux.createStore(immutableReducer);
```
< / div >
< / section >
## Solution
< section id = 'solution' >
```js
const immutableReducer = (state = [0,1,2,3,4,5], action) => {
switch(action.type) {
case 'REMOVE_ITEM':
return [
...state.slice(0, action.index),
...state.slice(action.index + 1)
];
default:
return state;
}
};
const removeItem = (index) => {
return {
type: 'REMOVE_ITEM',
index
}
}
const store = Redux.createStore(immutableReducer);
```
< / section >