A FormData polyfill

npm install formdata-polyfill

Meant to be used with babel, closer-compiler or equivalent (since it's written in es6 using class, WeakMap, Iterators, for...of)

This doesn't monkey patch xhr#send like Rob--W did here. However this provides you a way to convert the entire form to a blob and send it with xhr or fetch.

fd = new FormData(form)
xhr.send(fd._blob())

xhr.send(fd) // This don't work... Needs to be a native FormData

Another possible solution is to convert the form to a native FormData but then you would lose all the other methods not supported by the original FormData.

fd = new FormData(form)
fd._asNative() // returns a native formData with all the fields

The current status of the native FormData is this

This lib provides you all the function others don't include

• append with filename
• delete(), get(), getAll(), has(), set()
• entries(), keys(), values(), and support of for...of
• Available in web workers (yes, just include it...)

The reason why Rob--W's version didn't work for me was that it only works in web workers due to FileReaderSync beeing used. I did it with constructing new chunks with the blob constructor instead. new Blob([string, blob, file, etc])