How to use the sdp.getDtlsParameters function in sdp

function splitSimulcast(sdp) {
    const sections = SDPUtils.splitSections(sdp);
    const candidates = SDPUtils.matchPrefix(sections[1], 'a=candidate:');
    const dtls = SDPUtils.getDtlsParameters(sections[1], sections[0]);
    const ice = SDPUtils.getIceParameters(sections[1], sections[0]);
    const rtpParameters = SDPUtils.parseRtpParameters(sections[1]);

    // unified plan things.
    rtpParameters.headerExtensions = rtpParameters.headerExtensions.filter(ext => {
        return ext.uri !== 'urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id' &&
            ext.uri !== 'urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id' &&
            ext.uri !== 'urn:ietf:params:rtp-hdrext:sdes:mid';
    });
    sdp = 'v=0\r\n' +
      'o=mozilla...THIS_IS_SDPARTA-61.0 8324701712193024513 0 IN IP4 0.0.0.0\r\n' +
      's=-\r\n' +
      't=0 0\r\n' +
      'a=fingerprint:' + dtls.fingerprints[0].algorithm + ' ' + dtls.fingerprints[0].value + '\r\n' +
      'a=ice-ufrag:' + ice.usernameFragment + '\r\n' +
      'a=ice-pwd:' + ice.password + '\r\n' +

var dtlsTransport;
            var rtpSender;
            var rtpReceiver;
            var sendEncodingParameters;
            var recvEncodingParameters;
            var localCapabilities;

            var track;
            // FIXME: ensure the mediaSection has rtcp-mux set.
            var remoteCapabilities = SDPUtils.parseRtpParameters(mediaSection);
            var remoteIceParameters;
            var remoteDtlsParameters;
            if (!rejected) {
              remoteIceParameters = SDPUtils.getIceParameters(mediaSection,
                  sessionpart);
              remoteDtlsParameters = SDPUtils.getDtlsParameters(mediaSection,
                  sessionpart);
              remoteDtlsParameters.role = 'client';
            }
            recvEncodingParameters =
                SDPUtils.parseRtpEncodingParameters(mediaSection);

            var cname;
            // Gets the first SSRC. Note that with RTX there might be multiple
            // SSRCs.
            var remoteSsrc = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
                .map(function(line) {
                  return SDPUtils.parseSsrcMedia(line);
                })
                .filter(function(obj) {
                  return obj.attribute === 'cname';
                })[0];

var iceTransport;
      var dtlsTransport;
      var rtpReceiver;
      var sendEncodingParameters;
      var recvEncodingParameters;
      var localCapabilities;

      var track;
      // FIXME: ensure the mediaSection has rtcp-mux set.
      var remoteCapabilities = SDPUtils.parseRtpParameters(mediaSection);
      var remoteIceParameters;
      var remoteDtlsParameters;
      if (!rejected) {
        remoteIceParameters = SDPUtils.getIceParameters(mediaSection,
            sessionpart);
        remoteDtlsParameters = SDPUtils.getDtlsParameters(mediaSection,
            sessionpart);
        remoteDtlsParameters.role = 'client';
      }
      recvEncodingParameters =
          SDPUtils.parseRtpEncodingParameters(mediaSection);

      var rtcpParameters = SDPUtils.parseRtcpParameters(mediaSection);

      // Conference server will send all the ICE candidates in SDP
      //var isComplete = SDPUtils.matchPrefix(mediaSection,
      //    'a=end-of-candidates', sessionpart).length > 0;
      var isComplete = true;
      var cands = SDPUtils.matchPrefix(mediaSection, 'a=candidate:')
          .map(function(cand) {
            return SDPUtils.parseCandidate(cand);
          })

if (isIceLite) {
                  var cands = SDPUtils.matchPrefix(mediaSection, 'a=candidate:')
                  .map(function(cand) {
                    return SDPUtils.parseCandidate(cand);
                  })
                  .filter(function(cand) {
                    return cand.component === '1';
                  });
                  // ice-lite only includes host candidates in the SDP so we can
                  // use setRemoteCandidates (which implies an
                  // RTCIceCandidateComplete)
                  if (cands.length) {
                    iceTransport.setRemoteCandidates(cands);
                  }
                }
                var remoteDtlsParameters = SDPUtils.getDtlsParameters(
                    mediaSection, sessionpart);
                if (isIceLite) {
                  remoteDtlsParameters.role = 'server';
                }

                if (!self.usingBundle || sdpMLineIndex === 0) {
                  iceTransport.start(iceGatherer, remoteIceParameters,
                      isIceLite ? 'controlling' : 'controlled');
                  dtlsTransport.start(remoteDtlsParameters);
                }

                // Calculate intersection of capabilities.
                var params = self._getCommonCapabilities(localCapabilities,
                    remoteCapabilities);

                // Start the RTCRtpSender. The RTCRtpReceiver for this

var dtlsTransport;
            var rtpSender;
            var rtpReceiver;
            var sendEncodingParameters;
            var recvEncodingParameters;
            var localCapabilities;

            var track;
            // FIXME: ensure the mediaSection has rtcp-mux set.
            var remoteCapabilities = SDPUtils.parseRtpParameters(mediaSection);
            var remoteIceParameters;
            var remoteDtlsParameters;
            if (!rejected) {
              remoteIceParameters = SDPUtils.getIceParameters(mediaSection,
                  sessionpart);
              remoteDtlsParameters = SDPUtils.getDtlsParameters(mediaSection,
                  sessionpart);
              remoteDtlsParameters.role = 'client';
            }
            recvEncodingParameters =
                SDPUtils.parseRtpEncodingParameters(mediaSection);

            var cname;
            // Gets the first SSRC. Note that with RTX there might be multiple
            // SSRCs.
            var remoteSsrc = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
                .map(function(line) {
                  return SDPUtils.parseSsrcMedia(line);
                })
                .filter(function(obj) {
                  return obj.attribute === 'cname';
                })[0];

sections.forEach(function(mediaSection, sdpMLineIndex) {
        var transceiver = self.transceivers[sdpMLineIndex];
        var iceGatherer = transceiver.iceGatherer;
        var iceTransport = transceiver.iceTransport;
        var dtlsTransport = transceiver.dtlsTransport;
        var localCapabilities = transceiver.localCapabilities;
        var remoteCapabilities = transceiver.remoteCapabilities;

        var rejected = SDPUtils.isRejected(mediaSection);

        if (!rejected && !transceiver.isDatachannel) {
          var remoteIceParameters = SDPUtils.getIceParameters(
              mediaSection, sessionpart);
          var remoteDtlsParameters = SDPUtils.getDtlsParameters(
              mediaSection, sessionpart);
          if (isIceLite) {
            remoteDtlsParameters.role = 'server';
          }

          if (!self.usingBundle || sdpMLineIndex === 0) {
            iceTransport.start(iceGatherer, remoteIceParameters,
                isIceLite ? 'controlling' : 'controlled');
            dtlsTransport.start(remoteDtlsParameters);
          }

          // Calculate intersection of capabilities.
          var params = getCommonCapabilities(localCapabilities,
              remoteCapabilities);

          // Start the RTCRtpSender. The RTCRtpReceiver for this

if (isIceLite) {
                  var cands = SDPUtils.matchPrefix(mediaSection, 'a=candidate:')
                  .map(function(cand) {
                    return SDPUtils.parseCandidate(cand);
                  })
                  .filter(function(cand) {
                    return cand.component === '1';
                  });
                  // ice-lite only includes host candidates in the SDP so we can
                  // use setRemoteCandidates (which implies an
                  // RTCIceCandidateComplete)
                  if (cands.length) {
                    iceTransport.setRemoteCandidates(cands);
                  }
                }
                var remoteDtlsParameters = SDPUtils.getDtlsParameters(
                    mediaSection, sessionpart);
                if (isIceLite) {
                  remoteDtlsParameters.role = 'server';
                }

                if (!self.usingBundle || sdpMLineIndex === 0) {
                  iceTransport.start(iceGatherer, remoteIceParameters,
                      isIceLite ? 'controlling' : 'controlled');
                  dtlsTransport.start(remoteDtlsParameters);
                }

                // Calculate intersection of capabilities.
                var params = self._getCommonCapabilities(localCapabilities,
                    remoteCapabilities);

                // Start the RTCRtpSender. The RTCRtpReceiver for this

sections.forEach(function(mediaSection, sdpMLineIndex) {
        var transceiver = self.transceivers[sdpMLineIndex];
        var iceGatherer = transceiver.iceGatherer;
        var iceTransport = transceiver.iceTransport;
        var dtlsTransport = transceiver.dtlsTransport;
        var localCapabilities = transceiver.localCapabilities;
        var remoteCapabilities = transceiver.remoteCapabilities;

        var rejected = SDPUtils.isRejected(mediaSection);

        if (!rejected && !transceiver.isDatachannel) {
          var remoteIceParameters = SDPUtils.getIceParameters(
              mediaSection, sessionpart);
          var remoteDtlsParameters = SDPUtils.getDtlsParameters(
              mediaSection, sessionpart);
          if (isIceLite) {
            remoteDtlsParameters.role = 'server';
          }

          if (!self.usingBundle || sdpMLineIndex === 0) {
            iceTransport.start(iceGatherer, remoteIceParameters,
                isIceLite ? 'controlling' : 'controlled');
            dtlsTransport.start(remoteDtlsParameters);
          }

          // Calculate intersection of capabilities.
          var params = getCommonCapabilities(localCapabilities,
              remoteCapabilities);

          // Start the RTCRtpSender. The RTCRtpReceiver for this