FormData's append method does not match browsers

[domenic]

https://xhr.spec.whatwg.org/#interface-formdata

The append(name, value, filename) method, when invoked, must run these steps:​

See discussion in jsdom/jsdom#1533

Given this code:

var formData = new FormData();
var file = new Blob([
   JSON.stringify({})
], { type: 'application/json' });
formData.append('somename', file);
formData.entries().next().value

My reading is that per the spec this should append a new entry whose name is "somename" and whose value is a Blob to the form data. Then, entries().next().value should return the Blob right back.

However, apparently in Chrome and Firefox it does not do that. Instead it converts it to a File (not a Blob) with, at least in Chrome, name "blob".

[annevk]

Thanks for filing. I need to revert the remainder of f9d4c25. I thought someone would file an issue on that but I guess that didn't happen.