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web api instance method

Response: blob() method

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Available in workers

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

Syntax

blob()

Parameters

None.

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

Return value

A promise that resolves with a Blob whose data is the body’s bytes and the media type is the response’s Content-Type header’s value.

Exceptions

Examples

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

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

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also