freeCodeCamp/guide/english/certifications/front-end-libraries/redux/write-a-counter-with-redux/index.md

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Write a Counter with Redux

Write a Counter with Redux

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Problem Explanation

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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Hints

Hint 1

The best way to solve this challenge is by reviewing previous redux lessons particularly the following:

• Use const for Action Types
• Use a Switch Statement to Handle Multiple Actions
• Define an Action Creator
• Handle an Action in the Store
• Create a Redux Store

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Solutions

Solution 1 (Click to Show/Hide)

const INCREMENT = "INCREMENT"; // define a constant for increment action types
const DECREMENT = "DECREMENT"; // define a constant for decrement action types

// define the counter reducer which will increment or decrement the state based on the action it receives
const counterReducer = (state = 0, action) => {
  switch (action.type) {
    case INCREMENT:
      return (state += 1);

    case DECREMENT:
      return (state -= 1);

    default:
      return state;
  }
};

// define an action creator for incrementing
const incAction = () => {
  return {
    type: INCREMENT
  };
};

// define an action creator for decrementing
const decAction = () => {
  return {
    type: DECREMENT
  };
};

// define the Redux store here, passing in your reducers
const store = Redux.createStore(counterReducer);