When building modern web applications, it's common to make asynchronous calls to APIs to retrieve data. Managing these asynchronous calls can quickly become complex and repetitive, especially when dealing with multiple API endpoints or when handling complex data flows. Custom hooks can help alleviate these challenges by abstracting away the low-level details of making API calls and providing a simple and reusable interface to manage them. In this blog post, we will explore how to use custom hooks to gracefully make API calls.

What are custom hooks?

Custom hooks are a feature in React that allows developers to encapsulate logic and state in a reusable function. They are built using the useEffect and useState hooks and provide a way to share stateful logic between components without the need for inheritance or code duplication. Custom hooks can be used to encapsulate any functionality, but they are particularly useful for managing API calls.

The Basics of Making API Calls

Before we dive into custom hooks, let's review the basics of making API calls in React. There are several ways to make API calls in React, but one of the most popular is using the fetch function. The fetch function is a native browser API that allows you to send HTTP requests to a server and receive responses.

Here's an example of how to use the fetch function to make a simple API call:

fetch('https://api.example.com/data')
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error(error))

This code sends a GET request to the https://api.example.com/data endpoint and logs the response data to the console. If there is an error, it logs the error to the console as well.

Why use custom hooks for API calls?

Making API calls can be a complex task that involves a lot of state management and error handling. By creating custom hooks, developers can abstract this complexity away from their components and create a more maintainable codebase. Custom hooks can also provide a consistent interface for making API calls, making it easier to enforce coding standards and best practices.

Building a custom hook to manage API calls

To demonstrate how to use custom hooks to gracefully make API calls, we will create a hook that manages the state of an API request and handles errors.

import { useState, useEffect } from 'react';

const useApi = (url) => {
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);

  useEffect(() => {
    const fetchData = async () => {
      try {
        const response = await fetch(url);
        const json = await response.json();
        setData(json);
      } catch (error) {
        setError(error);
      } finally {
        setLoading(false);
      }
    };
    fetchData();
  }, [url]);

  return { data, loading, error };
};

export default useApi;

Let's break down what this custom hook is doing:

• We start by importing useState and useEffect from React.

• We define our custom hook called useApi. The hook takes a url as a parameter.

• We use useState to define the state variables data, loading, and error. We initialize loading to true because we want to indicate that the API call is in progress when the component first mounts.

• We define a useEffect hook that runs whenever the url changes. Inside this effect, we define an asynchronous function fetchData.

• fetchData sends an API request to the url using the fetch API. If the request is successful, it converts the response to JSON and sets the data state variable.

• If the request fails, it sets the error state variable to the error object.

• Finally, it sets the loading state variable to false, indicating that the API call has been completed.

• The hook returns an object containing the data, loading, and error state variables.

Using the custom hook in a component

Now that we have our custom hook, let's see how we can use it in a component.

import useApi from './useApi';

const MyComponent = () => {
  const { data, loading, error } = useApi('https://jsonplaceholder.typicode.com/todos/1');

  if (loading) {
    return <div>Loading...</div>;
  }

  if (error) {
    return <div>Error: {error.message}</div>;
  }

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

export default App;

In this example, we import the useApi hook and call it with the URL of the API endpoint. We destructure the data, error, and loading states from the returned object. We use these states to conditionally render a loading message or an error message. If the API call is successful, we render the data in an unordered list.

Conclusion

Custom hooks provide a powerful way to manage stateful logic in a reusable and composable way. In this blog, we explored how to use custom hooks to gracefully make API calls. By encapsulating the API call logic in a custom hook, we can easily reuse it across multiple components without duplicating code. Custom hooks can make our code more maintainable, testable, and scalable.