RTCPeerConnection.prototype.addIceCandidate = function()

in release/connect-rtc.js [4505:4587]
75 lines of code
27 McCabe index (conditional complexity)

  RTCPeerConnection.prototype.addIceCandidate = function(candidate) {
    var pc = this;
    var sections;
    if (candidate && !(candidate.sdpMLineIndex !== undefined ||
        candidate.sdpMid)) {
      return Promise.reject(new TypeError('sdpMLineIndex or sdpMid required'));
    }

    // TODO: needs to go into ops queue.
    return new Promise(function(resolve, reject) {
      if (!pc._remoteDescription) {
        return reject(makeError('InvalidStateError',
            'Can not add ICE candidate without a remote description'));
      } else if (!candidate || candidate.candidate === '') {
        for (var j = 0; j < pc.transceivers.length; j++) {
          if (pc.transceivers[j].rejected) {
            continue;
          }
          pc.transceivers[j].iceTransport.addRemoteCandidate({});
          sections = SDPUtils.getMediaSections(pc._remoteDescription.sdp);
          sections[j] += 'a=end-of-candidates\r\n';
          pc._remoteDescription.sdp =
              SDPUtils.getDescription(pc._remoteDescription.sdp) +
              sections.join('');
          if (pc.usingBundle) {
            break;
          }
        }
      } else {
        var sdpMLineIndex = candidate.sdpMLineIndex;
        if (candidate.sdpMid) {
          for (var i = 0; i < pc.transceivers.length; i++) {
            if (pc.transceivers[i].mid === candidate.sdpMid) {
              sdpMLineIndex = i;
              break;
            }
          }
        }
        var transceiver = pc.transceivers[sdpMLineIndex];
        if (transceiver) {
          if (transceiver.rejected) {
            return resolve();
          }
          var cand = Object.keys(candidate.candidate).length > 0 ?
              SDPUtils.parseCandidate(candidate.candidate) : {};
          // Ignore Chrome's invalid candidates since Edge does not like them.
          if (cand.protocol === 'tcp' && (cand.port === 0 || cand.port === 9)) {
            return resolve();
          }
          // Ignore RTCP candidates, we assume RTCP-MUX.
          if (cand.component && cand.component !== 1) {
            return resolve();
          }
          // when using bundle, avoid adding candidates to the wrong
          // ice transport. And avoid adding candidates added in the SDP.
          if (sdpMLineIndex === 0 || (sdpMLineIndex > 0 &&
              transceiver.iceTransport !== pc.transceivers[0].iceTransport)) {
            if (!maybeAddCandidate(transceiver.iceTransport, cand)) {
              return reject(makeError('OperationError',
                  'Can not add ICE candidate'));
            }
          }

          // update the remoteDescription.
          var candidateString = candidate.candidate.trim();
          if (candidateString.indexOf('a=') === 0) {
            candidateString = candidateString.substr(2);
          }
          sections = SDPUtils.getMediaSections(pc._remoteDescription.sdp);
          sections[sdpMLineIndex] += 'a=' +
              (cand.type ? candidateString : 'end-of-candidates')
              + '\r\n';
          pc._remoteDescription.sdp =
              SDPUtils.getDescription(pc._remoteDescription.sdp) +
              sections.join('');
        } else {
          return reject(makeError('OperationError',
              'Can not add ICE candidate'));
        }
      }
      resolve();
    });
  };