Mastering Data Management with TanStack Query

What is TanStack Query?

TanStack Query is a powerful library for fetching, caching, synchronizing, and updating asynchronous data in your React application. It provides an easy-to-use API that helps you manage data state and optimize your app’s performance.

Understanding Queries and Mutations

In TanStack Query, there are two main concepts: queries and mutations. Queries are used to fetch data, while mutations are used to update, create, or delete data. Both queries and mutations use the useQuery and useMutation hooks, respectively.

Mutations in TanStack Query

Mutations are a crucial part of data management in TanStack Query. They allow you to update, create, or delete data on the server. To achieve this, you can use the useMutation hook, which returns several useful properties, including isLoading, isSuccess, error, and mutate.

import { useMutation } from 'tanstack-query';

const { mutate, isLoading, isSuccess, error } = useMutation(
  async (newData) => {
    const response = await fetch('/api/data', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(newData),
    });
    return response.json();
  }
);

Handling Mutation Side Effects

When working with mutations, you often need to handle side effects, such as updating the data cache or displaying error messages. TanStack Query provides several callback functions to help you manage these side effects, including onMutate, onError, onSuccess, and onSettled.

import { useMutation } from 'tanstack-query';

const { mutate, isLoading, isSuccess, error } = useMutation(
  async (newData) => {
    // ...
  },
  {
    onMutate: () => {
      console.log('Mutation started');
    },
    onError: (error) => {
      console.error('Mutation failed:', error);
    },
    onSuccess: (data) => {
      console.log('Mutation succeeded:', data);
    },
    onSettled: () => {
      console.log('Mutation settled');
    },
  }
);

Invalidating Queries

When you update data using a mutation, you may need to invalidate the corresponding query to ensure that the updated data is reflected in your application. TanStack Query provides an invalidateQueries function that allows you to invalidate specific queries or all queries.

import { useQueryClient } from 'tanstack-query';

const queryClient = useQueryClient();

queryClient.invalidateQueries('data'); // Invalidate queries with key 'data'

Running Multiple Mutations in Parallel

Sometimes, you need to run multiple mutations simultaneously. TanStack Query provides a mutateAsync function that allows you to run multiple mutations in parallel and wait for them to complete.

import { useMutation } from 'tanstack-query';

const mutation1 = useMutation(async (newData) => {
  // ...
});

const mutation2 = useMutation(async (newData) => {
  // ...
});

Promise.all([mutation1.mutateAsync(), mutation2.mutateAsync()]).then(() => {
  console.log('All mutations completed');
});

Building a Real-World Application

To demonstrate the power of TanStack Query, we will build a simple to-do list application that uses mutations to create, update, and delete to-do items.

Note: I’ve added some example code snippets to illustrate the concepts, but you should replace them with your own implementation. Also, I’ve removed the conclusion section as per your request. Let me know if you need any further assistance!