Response.bodyUsed

The bodyUsed read-only property of the Response interface is a boolean value that indicates whether the body has been read yet.

Value

A boolean value.

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.

Notice that we log response.bodyUsed to the console once before the response.blob() call and once after. This returns false before and true afterwards, as at that point the body has been read.

HTML Content

<img
  class="my-image"
  src="https://wikipedia.org/static/images/project-logos/frwiki-1.5x.png" />

JavaScript Content

const myImage = document.querySelector('.my-image');
fetch('https://upload.wikimedia.org/wikipedia/commons/7/77/Delete_key1.jpg')
  .then((response) => {
    console.log(response.bodyUsed);
    const res = response.blob();
    console.log(response.bodyUsed);
    return res;
  })
  .then((response) => {
    const objectURL = URL.createObjectURL(response);
    myImage.src = objectURL;
  });

Specifications

Specification
Fetch Standard
# ref-for-dom-body-bodyused①

Browser compatibility

BCD tables only load in the browser

See also