Electron blob to buffer, I made this to use with the nativeImage class.

blob_to_buffer.js

function blob_to_buffer(blob, callback) {
	const file_reader = new FileReader()

	file_reader.addEventListener("loadend", event => {
		if (file_reader.error) {
			callback(file_reader.error)
		} else {
			callback(null, new Buffer(file_reader.result))
		}
	}, false)

	// Read the blob as a typed array.
	file_reader.readAsArrayBuffer(blob)

	// ⚠ Always test your error handling!
	// You can use this to do so!
	// file_reader.abort()
	
	// (When there's not an easy way to cause something to actually fail,
	// you can at least test sending an error callback, btw)
  
	return file_reader
}