Card events returned multiple times

[mm-ns]

Hi eveyone,

I have a simple local app angularjs app and that sends a request to my backend (nodejs) to read an nfc tag and get a response back.

this is my method handling the request:

`
var sent = false;

	nfc = new NFC();
	nfc.on('reader', reader => {
		reader.on('card', async card => {
			try {
				const textRecord = ndef.Utils.createTextRecord(card.uid);
				const message = new ndef.Message([textRecord]);
				const bytes = message.toByteArray();
				const data = encapsulate(Buffer.from(bytes.buffer));
				await reader.write(4, data); // starts writing in block 4, continues to 5 and 6 in order to 
				
				if (sent) {
					console.log("sent : ", sent);
					return;
				} else {
					sent = true;
					socketServer.emit('nfcScanned', {
						result: "success",
						data: card
					});
					console.log("SENDING RESPONSE ", sent);
					return res.json({
						// result: "success"
						result: "success",
						data: card
					});
				}
			} catch (err) {
				// if (sent) {
				// 	console.log("ALREADY SENT");
				// } else {
				// nfc = undefined;
				// socketServer.emit('nfcNotScanned', {
				// 	result: "failed",
				// 	error: err
				// });

				// // sent = true;
				// return res.json({
				// 	// result: "success"
				// 	result: "error",
				// 	data: card
				// });
				// }
			}
		});

		reader.on('card.off', card => {
			
		});

		reader.on('error', err => {
		
		});

		reader.on('end', () => {
			
		});


	});

	nfc.on('error', err => {
		console.error(err);
	});`

What happens is when i trigger this method call the first time, all is good and i get the uid back on the client. However, each subsequent call the client makes to scan a new tag and get the next uid, it returns the result multiple times (first req, 1 response; 2nd request 2 responses, n requests - n responses).

Regardless of whether i manage to reduce the number of events i emit back to the client (socket triggers multiple messages although the regular http response is only triggering once), the reader gets slower and slower to read/write tag and it gets sort of exponentially slower. any idea?

[mm-ns]

Update: that was my bad :/ the modal i used to add some "user friendliness" was instantiating my controller again resulting in triggering multiple events.