What is Axios? Fetch vs Axios: What’s the Difference?

When working with JavaScript, making HTTP requests is essential for modern web applications. This need has given rise to popular tools like the built-in Fetch API and the Axios library, each offering unique advantages and features. But exactly what is Axios, and how does it differ from JavaScript’s Fetch API?

This guide will answer the question “what is Axios” by covering its features, the benefits it brings over the JavaScript Fetch API, and use cases where each tool is most effective. By the end, you’ll understand when to use Axios versus Fetch and have a clear idea of which tool best meets your project needs.

What is Axios?

Axios is a popular JavaScript library for making HTTP requests from both browsers and Node.js. Built on top of JavaScript’s XMLHttpRequest, Axios simplifies making HTTP requests by offering a cleaner, feature-rich syntax. Unlike Fetch, which is minimal and requires some additional handling for tasks like parsing JSON or managing errors, Axios comes packed with built-in features to handle common requirements, such as automatic JSON parsing and request cancellation.

Key Features of Axios:

1. Automatic JSON Parsing: Axios automatically transforms JSON data, making it easier to work with data responses.
2. Simplified Error Handling: Axios catches HTTP status errors as well as network errors, making it easier to manage unsuccessful requests.
3. Request Cancellation: Axios provides built-in support for cancelling requests, which is helpful for scenarios where requests may become unnecessary (e.g., user navigates away).
4. Interceptors: Axios allows you to set up request and response interceptors, providing a way to preprocess or log requests and responses globally.
5. Wide Compatibility: Axios is compatible with older browsers and environments, making it suitable for legacy projects or cross-browser functionality.

Example of Using Axios

Make sure that you have installed axios by running:
npm i axios
and it is imported as
import axios from ‘axios’;

To get a quick feel for Axios, here’s a simple example that fetches data from a public API:

axios.get('https://jsonplaceholder.typicode.com/posts')
   .then(response => console.log(response.data))
   .catch(error => console.error('Axios error:', error));

The above code makes a GET request and automatically parses JSON data, allowing you to access it directly through response.data.

Understanding the JavaScript Fetch API

The Fetch API is a native JavaScript feature introduced in ES6, designed to handle HTTP requests in a lightweight, flexible way. Since it is built-in, you don’t need any external libraries to use Fetch. The Fetch API is based on promises, making it compatible with modern asynchronous JavaScript code.

Key Features of Fetch:

1. Native to JavaScript: No additional libraries are needed, as Fetch is built directly into modern browsers.
2. Promise-Based: Fetch uses promises, which makes handling asynchronous requests straightforward.
3. Basic HTTP Methods: Supports a variety of HTTP methods like GET, POST, PUT, and DELETE.
4. Lightweight and Flexible: Fetch provides basic functionality with no additional overhead, which is ideal for simple requests.

Example of Using JavaScript Fetch API

Here’s how you can make the same request as above using Fetch:

fetch('https://jsonplaceholder.typicode.com/posts')
   .then(response => {
      if (!response.ok) {
         throw new Error('Network response was not ok');
      }
      return response.json();
   })
   .then(data => console.log(data))
   .catch(error => console.error('Fetch error:', error));

Unlike Axios, Fetch requires you to parse the JSON data manually with response.json() and handle any HTTP status errors yourself.

Comparing Axios and Fetch: Key Differences

Now that we have a basic understanding of what Axios is and how it compares to Fetch, let’s dive into the primary differences between the two.

1. Automatic JSON Parsing

• Fetch: Requires you to call .json() on the response object to parse JSON data.
• Axios: Automatically parses JSON data, providing parsed data directly through response.data.

// Fetch
fetch(url)
   .then(response => response.json())
   .then(data => console.log(data));

// Axios
axios.get(url).then(response => console.log(response.data));

2. Error Handling

• Fetch: Only throws errors for network issues, requiring extra code to handle HTTP status errors like 404 or 500.
• Axios: Automatically detects HTTP status errors, making it easier to manage failed requests.

// Fetch error handling
fetch(url)
   .then(response => {
      if (!response.ok) {
         throw new Error('HTTP error');
      }
      return response.json();
   })
   .catch(error => console.error('Fetch error:', error));

// Axios error handling
axios.get(url).catch(error => console.error('Axios error:', error));

3. Request Cancellation

• Fetch: Requires an AbortController to cancel requests, which adds extra steps.
• Axios: Provides easy request cancellation using CancelToken.

// Fetch with AbortController
const controller = new AbortController();
fetch(url, { signal: controller.signal });
controller.abort(); // Cancels the request

// Axios cancellation
const source = axios.CancelToken.source();
axios.get(url, { cancelToken: source.token });
source.cancel('Request canceled');

4. Browser Compatibility

• Fetch: Supported in most modern browsers, but may require polyfills for older browsers.
• Axios: Works well with both modern and older browsers, providing more extensive compatibility.

5. Request and Response Interceptors

• Fetch: Lacks built-in support for interceptors.
• Axios: Comes with request and response interceptors, which are convenient for tasks like setting headers or logging requests.

Example of an Axios Interceptor:

axios.interceptors.request.use(
   config => {
      config.headers['Authorization'] = 'Bearer token';
      return config;
   },
   error => Promise.reject(error)
);

When to Use Fetch vs. Axios

Understanding what Axios is also includes knowing when to use it over Fetch. While both tools make HTTP requests effectively, each has unique strengths.

Use Fetch When:

• You prefer a native, minimalistic approach with fewer dependencies.
• Your project involves simple requests without the need for interceptors or cancellation.
• Browser compatibility is not a major issue, or polyfills are acceptable.

Use Axios When:

• You need automatic JSON parsing and simpler error handling.
• Your project requires request cancellation or interceptors for custom request handling.
• You are working with older browsers or require broader compatibility.

Advantages and Drawbacks of Fetch and Axios

Fetch API Pros:

• Built-in: No need for additional libraries.
• Lightweight: Basic features without added complexity.
• Promise-based: Cleaner syntax for async operations.

Fetch API Cons:

• Manual JSON Parsing: Requires calling response.json().
• Limited Error Handling: Only throws for network issues, not HTTP errors.
• No Request Cancellation: Requires an AbortController for cancellations.

Axios Pros:

• Automatic JSON Parsing: Saves coding time and reduces potential errors.
• Better Error Handling: Catches HTTP errors and network issues.
• Cancellation Support and Interceptors: Allows more flexible request handling.
• Cross-Browser Compatibility: Works with modern and older browsers.

Axios Cons:

• Extra Dependency: Requires installing an external library.
• Heavier: Adds some overhead compared to the minimal Fetch API.

Performance Considerations

In terms of performance, both Fetch and Axios are efficient, but their handling of data can impact application performance. Fetch’s minimalism means it may have a slight edge in very simple applications, while Axios’s features may result in faster development times and reduced code complexity, especially in complex applications.

FAQs on What is Axios and How It Differs from Fetch

Conclusion

Understanding “what is Axios” and how it differs from JavaScript’s Fetch API can help you make more informed choices when building modern web applications. Axios offers powerful features that save time and simplify code, making it particularly useful for applications with complex API interactions or cross-browser support needs. On the other hand, Fetch’s built-in nature and lightweight approach make it a viable choice for smaller projects or those where minimal dependencies are desired.

In sum, the decision to use Axios or Fetch depends largely on your project requirements, complexity, and browser compatibility considerations. Whichever tool you choose, mastering both can be valuable in the toolkit of any modern JavaScript developer, ensuring you can handle HTTP requests efficiently across different scenarios.