Using Axios for API Requests

What You’ll Learn 📚

• What Axios is and why it’s useful
• How to perform basic API requests using Axios
• Handling responses and errors
• Advanced Axios features like interceptors and configuration

Introduction to Axios

Axios is a popular JavaScript library used to make HTTP requests from the browser or Node.js. It’s promise-based, which means it allows you to write asynchronous code in a cleaner and more manageable way. Imagine Axios as your personal assistant who fetches data from the internet for you! 🌐

Key Terminology

• API (Application Programming Interface): A set of rules that allows different software entities to communicate with each other.
• HTTP Request: A message sent by a client to a server to request data or perform an action.
• Promise: An object representing the eventual completion or failure of an asynchronous operation.

Getting Started with Axios

Installation

First, let’s get Axios set up in your project. You can install it using npm or yarn:

npm install axios

yarn add axios

Simple Example: Fetching Data

const axios = require('axios'); // Importing Axios

// Making a GET request to a public API
axios.get('https://jsonplaceholder.typicode.com/posts/1')
  .then(response => {
    console.log(response.data); // Logging the response data
  })
  .catch(error => {
    console.error('Error fetching data:', error); // Handling errors
  });

{
  userId: 1,
  id: 1,
  title: 'sunt aut facere repellat provident occaecati excepturi optio reprehenderit',
  body: 'quia et suscipit...'
}

Progressively Complex Examples

Example 1: POST Request

axios.post('https://jsonplaceholder.typicode.com/posts', {
  title: 'foo',
  body: 'bar',
  userId: 1
})
.then(response => {
  console.log(response.data);
})
.catch(error => {
  console.error('Error posting data:', error);
});

Example 2: Handling Errors

axios.get('https://jsonplaceholder.typicode.com/invalid-url')
  .then(response => {
    console.log(response.data);
  })
  .catch(error => {
    if (error.response) {
      console.error('Server responded with a status:', error.response.status);
    } else if (error.request) {
      console.error('No response received:', error.request);
    } else {
      console.error('Error setting up request:', error.message);
    }
  });

Example 3: Using Interceptors

axios.interceptors.request.use(request => {
  console.log('Starting Request', request);
  return request;
});

axios.interceptors.response.use(response => {
  console.log('Response:', response);
  return response;
});

Common Questions and Answers

1. What is Axios?

   Axios is a promise-based HTTP client for JavaScript that can be used in the browser and Node.js.

2. How do I install Axios?

   You can install Axios using npm with npm install axios or yarn with yarn add axios.

3. Why use Axios over Fetch?

   Axios has a simpler API, supports older browsers, and provides features like request/response interceptors and automatic JSON transformation.

4. How do I handle errors in Axios?

   Use the .catch() method to handle errors. You can also inspect error.response, error.request, and error.message for more details.

5. Can Axios be used with async/await?

   Yes! Axios works seamlessly with async/await for cleaner asynchronous code.

6. What are interceptors in Axios?

   Interceptors are functions that Axios calls before a request is sent or after a response is received, allowing you to modify or log them.

7. How do I cancel a request in Axios?

   Use the CancelToken feature to create a cancel token and pass it to the request config.

8. How do I set default headers in Axios?

   You can set default headers using axios.defaults.headers.

9. What is the difference between axios.get() and axios.post()?

   axios.get() is used for fetching data, while axios.post() is used for sending data to a server.

10. How do I perform a PUT request with Axios?

    Use axios.put() and pass the URL and data as arguments.

11. Can I use Axios with React?

    Absolutely! Axios is commonly used in React applications for making API requests.

12. How do I handle timeouts in Axios?

    Set the timeout property in the request config to specify a timeout period.

13. How do I retry a failed request in Axios?

    You can use an interceptor to retry requests based on certain conditions.

14. What is the response format of Axios?

    Axios returns a response object containing data, status, headers, and more.

15. How do I configure Axios globally?

    Use axios.defaults to set global configurations like base URL and headers.

16. How do I use Axios with TypeScript?

    Axios has TypeScript support out of the box, providing type definitions for requests and responses.

17. How do I upload files with Axios?

    Use FormData to append files and send them with a POST request.

18. How do I handle large responses in Axios?

    Consider using streams or pagination to handle large data sets efficiently.

19. Can I use Axios with Vue.js?

    Yes, Axios is a popular choice for making HTTP requests in Vue.js applications.

20. How do I debug Axios requests?

    Use interceptors to log requests and responses, and check the network tab in your browser’s developer tools.

Troubleshooting Common Issues

If you encounter CORS errors, make sure the server you’re requesting data from allows cross-origin requests.

If your requests are failing, check your network connection and ensure the API endpoint is correct.

Remember, practice makes perfect! Try modifying the examples and see how Axios handles different scenarios.

Practice Exercises

• Make a GET request to a different API endpoint and log the response.
• Try sending a POST request with different data and observe the response.
• Implement error handling for a request and log specific error details.
• Use interceptors to log every request and response in your application.

For more information, check out the Axios documentation.