Integrating Redux to your React App — A Step by Step Guide

Integrating Redux into a React application can seem like a daunting task, but with a solid understanding of the basics and a step-by-step approach, it can be a breeze. In this article, we will go through the process of adding Redux to a React app from installing the necessary libraries to connecting your components to the store.

First things first, let's start by installing the "redux" and "react-redux" libraries via npm or yarn.

npm install redux react-redux

or

yarn add redux react-redux

These libraries provide the tools we need to create and manage the Redux store and connect it to our React components.

Once the libraries are installed, we will create a new directory called "store" in the root directory of our project. Inside "store", we will create three new files: "actions.js", "reducers.js", and "index.js".

In "actions.js", we will define our application's actions. An action is an object that describes a change to the application's state. For example, we might have an action called "addTodo" that adds a new to-do item to the application's state.

export const addTodo = (text) => {
    return {
        type: 'ADD_TODO',
        text: text
    }
}

Actions are the only way to change the state of the store and must have a "type" property that defines the type of action being performed.

Next, in "reducers.js", we will define our application's reducers. A reducer is a function that takes in the current state and an action, and returns the next state.

const initialState = {
    todos: []
}

export const todoReducer = (state = initialState, action) => {
    switch (action.type) {
        case 'ADD_TODO':
            return {
                ...state,
                todos: [...state.todos, { text: action.text }]
            }
        default:
            return state;
    }
}

It should handle each action by returning a new state that reflects the change described by the action. Reducers must be pure functions, meaning they should not modify the input state, but rather return a new state.

In "index.js", we will create a new store using the "createStore" function from the "redux" library. We will pass in our top-level reducer as the first argument.

import { createStore } from 'redux'
import { todoReducer } from './reducers'

const store = createStore(todoReducer)

The store is the single source of truth for our application's state and is where the state is kept, and actions are dispatched to update it.

In our root component, we will use the "Provider" component from the "react-redux" library to wrap our component tree. We will pass in the store we created in the previous step as a prop.

import { Provider } from 'react-redux'

const Root = () => {
  return (
    <Provider store={store}>
      <App />
    </Provider>
  );
}

This allows all child components to have access to the store and access the state and dispatch actions.

Now, let's move on to connecting our components to the store. To do this, we will use the "connect" function from the "react-redux" library. This function takes two arguments: a mapStateToProps function and a mapDispatchToProps function.

The mapStateToProps function maps the store's state to our component's props. This function takes in the state as an argument and returns an object that will be passed as props to the component. For example, if we want to pass the todos array from the state to our TodoList component as a prop, we can write a mapStateToProps function like this:

const mapStateToProps = (state) => {
    return {
        todos: state.todos
    }
}

The mapDispatchToProps function maps the store's dispatch method to our component's props. This function takes in the dispatch method as an argument and returns an object that will be passed as props to the component. For example, if we want to pass the addTodo action as a prop to our TodoForm component, we can write a mapDispatchToProps function like this:

import { addTodo } from './actions'

const mapDispatchToProps = (dispatch) => {
    return {
        addTodo: (text) => dispatch(addTodo(text))
    }
}

Finally, we will use the connect function to connect our component to the store and pass in the mapStateToProps and mapDispatchToProps functions as arguments.

import { connect } from 'react-redux'

const TodoList = (props) => {
    return (
        // TodoList component code
    )
}

export default connect(mapStateToProps, mapDispatchToProps)(TodoList)

By following these steps, our TodoList component will now have access to the todos array from the state as a prop, and the addTodo action as a prop. We can now use these props in our component to display the todos and add new todos to the state.

It's also worth mentioning that using middlewares like thunk can also enhance our application's ability to handle async actions, which is necessary for certain scenarios, like fetching data from an API.

In conclusion, integrating Redux into a React application is a powerful way to manage the state of your app, making it more predictable and easier to debug. By following the steps outlined in this article and understanding the basic concepts of actions, reducers, and the store, you can easily add Redux to your React application and take your development skills to the next level.

To make the best use of this setup, it is recommended to follow best practices such as keeping the store minimal, breaking down the state and action into smaller chunks and having minimal logic in the components.