JS axios header

JS axios header

![axios header](

Axios is a popular JavaScript library used to make HTTP requests from the browser or Node.js. It provides a simple and intuitive API for performing asynchronous operations, such as sending and receiving data over the network.

One of the common tasks while making HTTP requests is adding headers to the request. Headers contain additional information about the request or response, such as authentication tokens, content type, or custom data. In this article, we will explore how to use Axios to set headers in HTTP requests.

Installation

Before we begin, make sure you have Axios installed in your project. You can install Axios using npm or yarn with the following command:

npm install axios

Setting Headers in Axios

Axios provides a headers configuration option to set headers in the request. Here's an example:

import axios from 'axios';

const axiosInstance = axios.create({
  baseURL: '
  headers: {
    'Content-Type': 'application/json',
    Authorization: 'Bearer <your-access-token>',
  },
});

axiosInstance.get('/users')
  .then((response) => {
    console.log(response.data);
  })
  .catch((error) => {
    console.error(error);
  });

In the above example, we create an instance of Axios using axios.create and pass the headers configuration option with the desired headers. The Content-Type header is set to application/json, and the Authorization header is set to a bearer token.

Dynamic Headers

Sometimes, you may need to set headers dynamically based on certain conditions. In such cases, you can define a function that returns an object of headers. Here's an example:

import axios from 'axios';

const axiosInstance = axios.create({
  baseURL: '
  headers: () => {
    const headers = {
      'Content-Type': 'application/json',
    };

    if (isLoggedIn()) {
      headers.Authorization = `Bearer ${getToken()}`;
    }

    return headers;
  },
});

axiosInstance.get('/users')
  .then((response) => {
    console.log(response.data);
  })
  .catch((error) => {
    console.error(error);
  });

In the above example, we define a function as the value for the headers configuration option. Inside the function, we check if the user is logged in and add the Authorization header if they are.

Interceptors

Axios also provides interceptors that allow you to modify the headers before sending the request or after receiving the response. This is useful for scenarios where you need to add headers dynamically for every request or handle authentication errors.

Here's an example of adding an interceptor to set an access token header:

import axios from 'axios';

axios.interceptors.request.use((config) => {
  const token = getToken();

  if (token) {
    config.headers.Authorization = `Bearer ${token}`;
  }

  return config;
});

axios.get('
  .then((response) => {
    console.log(response.data);
  })
  .catch((error) => {
    console.error(error);
  });

In the above example, the axios.interceptors.request.use method is used to add a callback function that modifies the request configuration. Inside the callback function, we check if a token exists and add the Authorization header if it does.

Conclusion

Setting headers in Axios is a straightforward process. You can either set the headers directly in the headers configuration option or use interceptors to modify the headers dynamically. Headers are essential for sending and receiving data over the network securely, and Axios provides a convenient way to handle them in your JavaScript applications.

Axios is a powerful library for making HTTP requests, and understanding how to set headers will help you build more robust and secure applications.

References

• [Axios GitHub Repository](
• [Axios Documentation](

gantt
    title Axios Header Implementation

    section Setup
    Install Axios: 0, 2d

    section Setting Headers
    Create Axios instance: 2d, 2d
    Set headers in the instance: 2d, 3d
    Send request with headers: 5d, 2d

    section Dynamic Headers
    Create dynamic headers function: 8d, 2d
    Modify headers based on conditions: 8d, 2d
    Send request with dynamic headers: 10d, 2d

    section Interceptors
    Add interceptor for headers: 13d, 2d
    Modify headers in the interceptor: 13d, 2d
    Send request with interceptors: 15d, 2d

flowchart TD
    A[Start] --> B{Create Axios instance}
    B --> C[Set headers in the instance]
    C --> D[Send request with headers]
    D --> E{Dynamic Headers}
    E --> F[Create dynamic headers function