Body.bodyUsed

The bodyUsed read-only property of the Body mixin contains a Boolean that indicates whether the body has been read yet.

Syntax

var myBodyUsed = response.bodyUsed;

Value

A Boolean.

Example

In our fetch request example (run fetch request live), we create a new request using the Request.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">

JS Content

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

Specifications

Browser compatibility

[1] Behind a preference in version 41.

[2] Behind a preference starting with version 34.

[3] Behind a preference in version 28.

See also

• ServiceWorker API
• HTTP access control (CORS)
• HTTP