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How to Make an HTTP Request in Javascript

Gloria Akintunde's photo
Gloria Akintunde
·

3 min read

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HTTP requests are a critical aspect of web development. They allow web developers to interact with remote servers and fetch or submit data from within a web application. Javascript is a powerful language that can be used to create HTTP requests easily. In this article, we will learn how to make HTTP requests in Javascript.

Making a Simple HTTP Request with Javascript

Making a simple HTTP request using Javascript is easy. All you need is an XMLHttpRequest object. Here are the steps to create an HTTP request:

  1. Create an XMLHttpRequest object:
const xhr = new XMLHttpRequest();
  1. Open the request with the desired HTTP method and URL:
xhr.open('GET', 'https://example.com');
  1. Send the request:
xhr.send();
  1. Handle the response:
xhr.onload = function() {
    if (xhr.status === 200) {
        console.log(xhr.response);
    }
    else {
        console.log('Request failed. Returned status of ' + xhr.status);
    }
};

In the example above, we have made a simple HTTP GET request to https://example.com. The onload function handles the response from the server.

Making an HTTP Request with the Fetch API

The Fetch API is a modern way of making HTTP requests in Javascript. It is a simpler and cleaner way of making HTTP requests than the traditional XMLHttpRequest method. Here are the steps to create an HTTP request using the Fetch API:

  1. Create a Fetch request:
fetch('https://example.com')
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error(error));

In the example above, we have made an HTTP GET request to https://example.com. The then function handles the response from the server.

Advanced HTTP Requests with Javascript

There are several advanced techniques you can use to make HTTP requests with Javascript.

Using Promises with HTTP requests

Promises are a modern way of handling asynchronous code in Javascript. You can use promises to make HTTP requests. Here is an example:

function makeRequest(url) {
  return new Promise(function(resolve, reject) {
    const xhr = new XMLHttpRequest();
    xhr.open('GET', url);
    xhr.onload = function() {
      if (xhr.status === 200) {
        resolve(xhr.response);
      } else {
        reject(Error(xhr.statusText));
      }
    };
    xhr.onerror = function() {
      reject(Error("Network Error"));
    };
    xhr.send();
  });
}

makeRequest('https://example.com')
  .then(function(response) {
    console.log(response);
  })
  .catch(function(error) {
    console.log(error);
  });

Making HTTP Requests with async/await

The async/await feature in Javascript makes asynchronous programming easier to read and write. You can use async/await to make HTTP requests. Here is an example:

async function makeRequest(url) {
  const response = await fetch(url);
  const data = await response.json();
  return data;
}

makeRequest('https://example.com')
  .then(data => console.log(data))
  .catch(error => console.error(error));

Sending HTTP Requests with Headers

HTTP headers allow the client and server to pass additional information with an HTTP request or response. You can send headers with your HTTP requests using the Fetch API. Here is an example:

fetch('https://example.com', {
  headers: {
    'Authorization': 'Bearer my-token',
    'Content-Type': 'application/json'
  }
})
  .then(response => response.json())
  .then(data

\=> console.log(data)) .catch(error => console.error(error));


### Sending Data with HTTP Requests

You can send data with your HTTP requests using the Fetch API. Here is an example:

```javascript
fetch('https://example.com', {
  method: 'POST',
  body: JSON.stringify({ message: 'Hello World' }),
  headers: {
    'Content-Type': 'application/json'
  }
})
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error(error));

In the example above, we are making an HTTP POST request with a JSON payload containing a message key with the value of Hello World.

Conclusion

In this article, we have learned how to make HTTP requests in Javascript. We have covered how to make simple HTTP requests using XMLHttpRequest and how to make HTTP requests using the Fetch API. We have also covered advanced techniques such as using promises and async/await, sending headers and data with HTTP requests. By mastering these techniques, you will be able to create powerful web applications that interact with remote servers. Happy coding!

JavaScriptWeb Development