What is response writeHead in node JS?

Like most Node. js functions, createServer() takes a callback function as an argument. The callback function begins by calling the response. writeHead() method. This method sends an HTTP status code and a collection of response headers back to the client.

What does Response setHeader do?

setHeader(name, value) (Added in v0. 4.0) method is an inbuilt application programming interface of the ‘http’ module which sets a single header value for implicit headers. If this header already exists in the to-be-sent headers, its value will be replaced. writeHead(), with the headers passed to response.

What is the use of fetch in node JS?

Fetch API is one of the simplest way to make asynchronous HTTP request in the web browser. It uses JS Promises to deliver more flexible features for making requests on the browser. Fetch method returns a Promise so we can make use of . then() and .

What is callback in node JS?

Callback is an asynchronous equivalent for a function. A callback function is called at the completion of a given task. Node makes heavy use of callbacks. This makes Node. js highly scalable, as it can process a high number of requests without waiting for any function to return results.

What is the difference between setHeader and writeHead?

The difference between setHeader and writeHead is that setHeader sets one header at a time, and you can use as many setHeader methods as you need before you send the response. This also means any headers with the same name in both setHeader and writeHead will be overwritten by writeHead headers.

What is the difference between setHeader and addHeader methods?

Both setHeader() and addHeader() will add a header and value to the response if the header is not already in the response. The difference between set and add shows up when the header is there. In that case: setHeader() overwrites the existing value, whereas addHeader() adds an additional value.

What is response in JS?

Response : Object Represents a response from a web request initiated by fetch(). fetch(), Request and Response are a new, low level replacement for XMLHttpRequest.

What is the response object?

The response object is an instance of a javax. servlet. http. Just as the server creates the request object, it also creates an object to represent the response to the client. The response object also defines the interfaces that deal with creating new HTTP headers.

Why is Axios better than fetch?

Axios has the ability to intercept HTTP requests. Fetch, by default, doesn’t provide a way to intercept requests. Axios has built-in support for download progress. Fetch does not support upload progress.

What is fetch method?

The fetch() method in JavaScript is used to request to the server and load the information in the webpages. The request can be of any APIs that returns the data of the format JSON or XML. This method returns a promise.