53 lines
2.0 KiB
Markdown
53 lines
2.0 KiB
Markdown
---
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title: Write a Counter with Redux
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---
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## Write a Counter with Redux
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The goal of this challenge is to apply all the concepts learned from previous Redux challenges and create a simple counter that will increment or decrement a state by 1.
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### Hint 1
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The best way to solve this challenge is by reviewing previous redux lessons particularly the following:
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- [Use const for Action Types](https://learn.freecodecamp.org/front-end-libraries/redux/use-const-for-action-types/)
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- [Use a Switch Statement to Handle Multiple Actions](https://learn.freecodecamp.org/front-end-libraries/redux/use-a-switch-statement-to-handle-multiple-actions/)
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- [Define an Action Creator](https://learn.freecodecamp.org/front-end-libraries/redux/define-an-action-creator/)
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- [Handle an Action in the Store](https://learn.freecodecamp.org/front-end-libraries/redux/handle-an-action-in-the-store/)
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- [Create a Redux Store](https://learn.freecodecamp.org/front-end-libraries/redux/create-a-redux-store)
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### Solution
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```javascript
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const INCREMENT = 'INCREMENT'; // define a constant for increment action types
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const DECREMENT = 'DECREMENT'; // define a constant for decrement action types
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// define the counter reducer which will increment or decrement the state based on the action it receives
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const counterReducer = (state = 0, action) => {
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switch(action.type){
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case INCREMENT:
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return state+=1;
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case DECREMENT:
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return state-=1;
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default:
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return state;
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}
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} ;
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// define an action creator for incrementing
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const incAction = () => {
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return {
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type: INCREMENT
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}
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};
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// define an action creator for decrementing
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const decAction = () => {
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return {
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type: DECREMENT
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}
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};
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// define the Redux store here, passing in your reducers
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const store = Redux.createStore(counterReducer);
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```
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