device.write(data) able to send response with number of bytes written to device?

[filipinacoder]

Hello! I would like to ask if it is possible for device.write(data) to be able to give us a response with the number of bytes written to a device?

Would really appreciate it if you can somehow shed some light, or point where to extract this.

Thanks and have a good day.

[natevw]

There is precedent for this in fs.write where:

The callback will be given three arguments (err, bytesWritten, buffer) where bytesWritten specifies how many bytes were written from buffer.

Likewise, the underlying call is to hid_write:

This function returns the actual number of bytes written and -1 on error.

I haven't reviewed when/why the actual number of bytes will be different, but +1 that we should pass the value back to JS.

The C++ write wrapper would need to return that value on success, and then the JS bridge NAN_METHOD(HID::write) needs to take that to use as its NanReturnValue.