Simplifying State Management and Data Fetching in React with Redux Toolkit Query
Tags: react, redux, frontend, javascript
Published: 2024-07-01 03:47:15

## Efficient Data Fetching and Cache Management with RTK Query: A Comprehensive Guide

Managing state and data fetching in React can be challenging. Redux Toolkit Query (RTK Query) simplifies this process. In this post, we'll explore the `useGetTodosQuery` hook and its options, including polling and `tagTypes`.

## Key Points for Using Options

- **pollingInterval**: Use when you need to keep data updated at regular intervals.
- **refetchOnMountOrArgChange**: Use when you need to refetch data upon component mount or when query arguments change.
- **refetchOnReconnect**: Use when you want data to refresh after regaining network connectivity.
- **refetchOnFocus**: Use when you need data to refresh when the browser window regains focus.
- **skip**: Use to conditionally skip a query.
- **tagTypes**: Use for more efficient data fetching and cache management.

## What is Redux Toolkit Query?

RTK Query is a data fetching and caching tool built on top of Redux Toolkit. It helps manage API requests, caching, and state synchronization with your Redux store.

## Setting Up RTK Query

### Step 1: Install Redux Toolkit

```bash
npm install @reduxjs/toolkit react-redux
```

### Step 2: Create an API Slice

Create an `apiSlice.js` file:

```javascript
import { createApi, fetchBaseQuery } from '@reduxjs/toolkit/query/react';

export const apiSlice = createApi({
  reducerPath: 'api',
  baseQuery: fetchBaseQuery({ baseUrl: '/api' }),
  tagTypes: ['Todo'],
  endpoints: (builder) => ({
    getTodos: builder.query({
      query: () => 'todos',
      providesTags: ['Todo'],
    }),
    updateTodo: builder.mutation({
      query: (todo) => ({
        url: `todos/${todo.id}`,
        method: 'PUT',
        body: todo,
      }),
      invalidatesTags: ['Todo'],
    }),
  }),
});

export const { useGetTodosQuery, useUpdateTodoMutation } = apiSlice;
```

### Step 3: Configure the Store

```javascript
import { configureStore } from '@reduxjs/toolkit';
import { apiSlice } from './apiSlice';

const store = configureStore({
  reducer: {
    [apiSlice.reducerPath]: apiSlice.reducer,
  },
  middleware: (getDefaultMiddleware) =>
    getDefaultMiddleware().concat(apiSlice.middleware),
});

export default store;
```

### Step 4: Provide the Store

```javascript
import React from 'react';
import ReactDOM from 'react-dom';
import { Provider } from 'react-redux';
import store from './store';
import App from './App';

ReactDOM.render(
  <Provider store={store}>
    <App />
  </Provider>,
  document.getElementById('root')
);
```

## Using `useGetTodosQuery` with Options

### Efficient Data Fetching with `tagTypes`

Using `pollingInterval` can lead to unnecessary API calls, especially when data doesn't change frequently. A more efficient approach is to use `tagTypes` and invalidating tags to refetch data only when necessary. This approach ensures the UI stays in sync without constant polling.

### Example Usage

Here’s how to use `useGetTodosQuery` and `useUpdateTodoMutation` in a React component:

```javascript
import React from 'react';
import { useGetTodosQuery, useUpdateTodoMutation } from './apiSlice';

const TodoList = () => {
  const { data: todos, isLoading, isError } = useGetTodosQuery();
  const [updateTodo] = useUpdateTodoMutation();

  const handleUpdate = async (todo) => {
    await updateTodo({ ...todo, completed: !todo.completed });
  };

  if (isLoading) return <div>Loading...</div>;
  if (isError) return <div>Error loading todos</div>;

  return (
    <ul>
      {todos.map((todo) => (
        <li key={todo.id}>
          {todo.title}
          <button onClick={() => handleUpdate(todo)}>
            {todo.completed ? 'Mark Incomplete' : 'Mark Complete'}
          </button>
        </li>
      ))}
    </ul>
  );
};

export default TodoList;
```

### Complete Example with Options

Here’s a complete example using `useGetTodosQuery` with various options:

```javascript
import React from 'react';
import { useGetTodosQuery } from './apiSlice';

const TodoList = () => {
  const { data: todos, isLoading, isError } = useGetTodosQuery(undefined, {
    refetchOnMountOrArgChange: true,
    refetchOnReconnect: true,
    refetchOnFocus: true,
    skip: false,
  });

  if (isLoading) return <div>Loading...</div>;
  if (isError) return <div>Error loading todos</div>;

  return (
    <ul>
      {todos.map((todo) => (
        <li key={todo.id}>{todo.title}</li>
      ))}
    </ul>
  );
};

export default TodoList;
```

## Polling Intervals vs. Tag Types

### When to Use Polling Intervals

Polling intervals are useful when data changes frequently and needs to be updated in real-time. For example:
- Live sports scores
- Stock market data
- Real-time chat messages

### When to Use `tagTypes`

`tagTypes` are better suited for scenarios where data changes infrequently or when you want to minimize API calls. For example:
- User profile information
- Product details in an e-commerce app
- Todo lists where updates are user-driven

Using `tagTypes` with invalidation tags ensures data is refetched only when necessary, reducing unnecessary network traffic and improving performance.

## Conclusion

RTK Query makes data fetching in React applications simple and efficient. While polling is useful for frequently updated data, using `tagTypes` and invalidating tags is a better approach for efficient data fetching and cache management. This method ensures your UI stays up-to-date without unnecessary API calls. Happy coding!