[web-nfc] Shall we obtain and compare the ScanOptions? (#557)

DonnaWuDongxia has just created a new issue for https://github.com/w3c/web-nfc:

== Shall we obtain and compare the ScanOptions? ==
In the spec:
https://w3c.github.io/web-nfc/#the-ndefreader-and-ndefwriter-objects

> Note that the internal slots of NDEFReader come from the options passed to NDEFReader.scan(). Therefore there is maximum one filter associated with any given NDEFReader object and successive invocations of NDEFReader.scan() with new options will replace existing filters.

```
dictionary NDEFScanOptions {
  USVString id;
  USVString recordType;
  USVString mediaType;
  AbortSignal? signal;
};
```
It aims to replace the filters for a reader. The question is what the expection if the |options| is identical or equals? Reject the successive _Scan_? And what if the signal is identical but other memebers not equals?

So the phase 

> with **new** options
is not eaily to identify.

Can we just define the action as replaceing the previous filter no matter the successive invocations of NDEFReader.scan() takes? The previous scan will onerror, or the signal passed to previous scan invocation will be aborted if there is. Just like SignalAbort on current scan + A new Reader.Scan().

Please view or discuss this issue at https://github.com/w3c/web-nfc/issues/557 using your GitHub account

Received on Tuesday, 7 April 2020 08:54:27 UTC