How do I read a 16-bit int from a Uint8List in Dart?

Question

I have a binary data stored in Uint8List and I'd like to read a 16-bit int from that list. Are there any convenience methods to help with this?

(paraphrasing from a conversation I had with a colleague)

Answer 1

You can use the ByteData class:

var buffer = new Uint8List(8).buffer;
var bytes = new ByteData.view(buffer);
bytes.getUint16(offset);

(paraphrased from an answer provided by a colleague)

Answer 2

As Seth said, you want a ByteData view of the Uint8List binary data.

It is slightly better to use ByteBuffer.asByteData(). It is a little more concise and works better for testing. If you have a mock Uint8List and a mock ByteBuffer, new ByteData.view(buffer) will fail, but the mock ByteBuffer's asByteData() method could be made to return a mock ByteData.

var bytes = myUint8List.buffer.asByteData();
bytes.getUint16(offset);

With perfect foresight we would only have asByteData() and not also a redundant public ByteData.view constructor.