dataUrlToBlob ignores type parameters and assumes base64-encoding

[Treora]

As remarked in #61:

a quick look at this library’s dataUrlToBlob() implementation reveals however that it throws away all of the media type parameters! And blindly assumes base64 encoding.

Current implementation:

export function dataURLToBlob (dataURL: string): Blob {
  var type = dataURL.match(/data:([^;]+)/)[1]
  var base64 = dataURL.replace(/^[^,]+,/, '')

  var buff = binaryStringToArrayBuffer(atob(base64))
  return createBlob([buff], { type: type })
}

Issues:

• A data url without ;base64 appended to the media type should just percent-decode the data.

• The type should include its parameters; for example, in text/plain;charset=iso-8859-5 (used with or without the base64-encoding), dropping the charset parameter might result in problems when decoding the blob’s data.

[nolanlawson]

Yep, this is true! I assumed base64 encoding for data URLs (for both input and output).