Request

The Request interface of the Fetch API represents a resource request.

You can create a new Request object using the Request() constructor, but you are more likely to encounter a Request object being returned as the result of another API operation, such as a service worker FetchEvent.request.

Constructor

Request()
Creates a new Request object.

Properties

Request.body Read only
A ReadableStream of the body contents.
Request.bodyUsed Read only
Stores true or false to indicate whether or not the body has been used in a request yet.
Request.cache Read only
Contains the cache mode of the request (e.g., default, reload, no-cache).
Request.credentials Read only
Contains the credentials of the request (e.g., omit, same-origin, include). The default is same-origin.
Request.destination Read only
Returns a string describing the request's destination. This is a string indicating the type of content being requested.
Request.headers Read only
Contains the associated Headers object of the request.
Request.integrity Read only
Contains the subresource integrity value of the request (e.g., sha256-BpfBw7ivV8q2jLiT13fxDYAe2tJllusRSZ273h2nFSE=).
Request.method Read only
Contains the request's method (GET, POST, etc.)
Request.mode Read only
Contains the mode of the request (e.g., cors, no-cors, same-origin, navigate.)
Request.redirect Read only
Contains the mode for how redirects are handled. It may be one of follow, error, or manual.
Request.referrer Read only
Contains the referrer of the request (e.g., client).
Request.referrerPolicy Read only
Contains the referrer policy of the request (e.g., no-referrer).
Request.url Read only
Contains the URL of the request.

Methods

Request.arrayBuffer()
Returns a promise that resolves with an ArrayBuffer representation of the request body.
Request.blob()
Returns a promise that resolves with a Blob representation of the request body.
Request.clone()
Creates a copy of the current Request object.
Request.formData()
Returns a promise that resolves with a FormData representation of the request body.
Request.json()
Returns a promise that resolves with the result of parsing the request body as JSON.
Request.text()
Returns a promise that resolves with a text representation of the request body.

Note: The request body functions can be run only once; subsequent calls will resolve with empty strings/ArrayBuffers.

Examples

In the following snippet, we create a new request using the Request() constructor (for an image file in the same directory as the script), then return some property values of the request:

const request = new Request('https://www.mozilla.org/favicon.ico');

const url = request.url;
const method = request.method;
const credentials = request.credentials;

You could then fetch this request by passing the Request object in as a parameter to a WindowOrWorkerGlobalScope.fetch() call, for example:

fetch(request)
  .then(response => response.blob())
  .then(blob => {
    image.src = URL.createObjectURL(blob);
  });

In the following snippet, we create a new request using the Request() constructor with some initial data and body content for an api request which need a body payload:

const request = new Request('https://example.com', {method: 'POST', body: '{"foo": "bar"}'});

const url = request.url;
const method = request.method;
const credentials = request.credentials;
const bodyUsed = request.bodyUsed;

Note: The body type can only be a Blob, BufferSource, FormData, URLSearchParams, USVString or ReadableStream type, so for adding a JSON object to the payload you need to stringify that object.

You could then fetch this api request by passing the Request object in as a parameter to a WindowOrWorkerGlobalScope.fetch() call, for example and get the response:

fetch(request)
  .then(response => {
    if (response.status === 200) {
      return response.json();
    } else {
      throw new Error('Something went wrong on api server!');
    }
  })
  .then(response => {
    console.debug(response);
    // ...
  }).catch(error => {
    console.error(error);
  });

Specifications

Specification
Fetch Standard (Fetch)
# request-class

Browser compatibility

BCD tables only load in the browser

See also