ContextQMD
Back to Content

Response: blob() method

files/en-us/web/api/response/blob/index.md

latest2.4 KB
Original Source

{{APIRef("Fetch API")}}{{AvailableInWorkers}}

The blob() method of the {{domxref("Response")}} interface takes a {{domxref("Response")}} stream and reads it to completion. It returns a promise that resolves with a {{domxref("Blob")}}.

Syntax

js-nolint
blob()

Parameters

None.

[!NOTE] If the {{domxref("Response")}} has a {{domxref("Response.type")}} of "opaque", the resulting {{domxref("Blob")}} will have a {{domxref("Blob.size")}} of 0 and a {{domxref("Blob.type")}} of empty string "", which renders it useless for methods like {{domxref("URL.createObjectURL_static", "URL.createObjectURL()")}}.

Return value

A promise that resolves with a {{domxref("Blob")}} whose data is the body's bytes and the media type is the response's Content-Type header's value.

Exceptions

  • AbortError {{domxref("DOMException")}}
  • {{jsxref("TypeError")}}
    • : Thrown for one of the following reasons:
      • The response body is disturbed or locked.
      • There was an error decoding the body content (for example, because the {{httpheader("Content-Encoding")}} header is incorrect).

Examples

In our fetch request example (run fetch request live), we create a new request using the {{domxref("Request.Request","Request()")}} constructor, then use it to fetch a JPG. When the fetch is successful, we read a {{domxref("Blob")}} out of the response using blob(), put it into an object URL using {{domxref("URL.createObjectURL_static", "URL.createObjectURL()")}}, and then set that URL as the source of an {{htmlelement("img")}} element to display the image.

js
const myImage = document.querySelector("img");

const myRequest = new Request("flowers.jpg");

fetch(myRequest)
  .then((response) => response.blob())
  .then((myBlob) => {
    const objectURL = URL.createObjectURL(myBlob);
    myImage.src = objectURL;
  });

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also