RTCErrorEvent: error property

An RTCError object whose properties provide details about the error which has occurred in the context of a WebRTC operation.

In this example, a handler is established for an RTCDataChannel's error event.

dataChannel.addEventListener("error", (event) => {
  let error = event.error;

  if (error.errorDetail === "sdp-syntax-error") {
    let errLine = error.sdpLineNumber;
    let errMessage = error.message;

    let alertMessage = `A syntax error occurred interpreting line ${errLine} of the SDP: ${errMessage}`;
    showMyAlertMessage("Data Channel Error", alertMessage);
  } else {
    terminateMyConnection();
  }
});

If the error is an SDP syntax error—indicated by its errorDetail property being sdp-syntax-error—, a message string is constructed to present the error message and the line number within the SDP at which the error occurred. This message is then displayed using a function called showMyAlertMessage(), which stands in for whatever output mechanism this code might use.

Any other error is treated as terminal, causing a terminateMyConnection() function to be called.

The above example uses addEventListener() to add the handler for error events. You can also use the RTCDataChannel object's onerror event handler property, like this:

dataChannel.onerror = (event) => {
  let error = event.error;

  /* and so forth */
};