diff --git a/src/js/chrome/chrome_shim.js b/src/js/chrome/chrome_shim.js
index 2eecce0e..a6c39503 100644
--- a/src/js/chrome/chrome_shim.js
+++ b/src/js/chrome/chrome_shim.js
@@ -34,7 +34,7 @@ export function shimOnTrack(window) {
     const origSetRemoteDescription =
         window.RTCPeerConnection.prototype.setRemoteDescription;
     window.RTCPeerConnection.prototype.setRemoteDescription =
-      function setRemoteDescription() {
+      function setRemoteDescription(description, ...args) {
         if (!this._ontrackpoly) {
           this._ontrackpoly = (e) => {
             // onaddstream does not fire when a track is added to an existing
@@ -73,7 +73,7 @@ export function shimOnTrack(window) {
           };
           this.addEventListener('addstream', this._ontrackpoly);
         }
-        return origSetRemoteDescription.apply(this, arguments);
+        return origSetRemoteDescription.apply(this, [description, ...args]);
       };
   } else {
     // even if RTCRtpTransceiver is in window, it is only used and
@@ -119,8 +119,8 @@ export function shimGetSendersWithDtmf(window) {
       };
       const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
       window.RTCPeerConnection.prototype.addTrack =
-        function addTrack(track, stream) {
-          let sender = origAddTrack.apply(this, arguments);
+        function addTrack(track, ...args) {
+          let sender = origAddTrack.apply(this, [track, ...args]);
           if (!sender) {
             sender = shimSenderWithDtmf(this, track);
             this._senders.push(sender);
@@ -130,8 +130,8 @@ export function shimGetSendersWithDtmf(window) {
 
       const origRemoveTrack = window.RTCPeerConnection.prototype.removeTrack;
       window.RTCPeerConnection.prototype.removeTrack =
-        function removeTrack(sender) {
-          origRemoveTrack.apply(this, arguments);
+        function removeTrack(sender, ...args) {
+          origRemoveTrack.apply(this, [sender, ...args]);
           const idx = this._senders.indexOf(sender);
           if (idx !== -1) {
             this._senders.splice(idx, 1);
@@ -206,11 +206,12 @@ export function shimSenderReceiverGetStats(window) {
 
     const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
     if (origAddTrack) {
-      window.RTCPeerConnection.prototype.addTrack = function addTrack() {
-        const sender = origAddTrack.apply(this, arguments);
-        sender._pc = this;
-        return sender;
-      };
+      window.RTCPeerConnection.prototype.addTrack =
+        function addTrack(track, ...args) {
+          const sender = origAddTrack.apply(this, [track, ...args]);
+          sender._pc = this;
+          return sender;
+        };
     }
     window.RTCRtpSender.prototype.getStats = function getStats() {
       const sender = this;
@@ -252,10 +253,10 @@ export function shimSenderReceiverGetStats(window) {
 
   // shim RTCPeerConnection.getStats(track).
   const origGetStats = window.RTCPeerConnection.prototype.getStats;
-  window.RTCPeerConnection.prototype.getStats = function getStats() {
-    if (arguments.length > 0 &&
-        arguments[0] instanceof window.MediaStreamTrack) {
-      const track = arguments[0];
+  window.RTCPeerConnection.prototype.getStats = function getStats(...args) {
+    if (args.length > 0 &&
+        args[0] instanceof window.MediaStreamTrack) {
+      const track = args[0];
       let sender;
       let receiver;
       let err;
@@ -291,7 +292,7 @@ export function shimSenderReceiverGetStats(window) {
         'There is no sender or receiver for the track.',
         'InvalidAccessError'));
     }
-    return origGetStats.apply(this, arguments);
+    return origGetStats.apply(this, args);
   };
 }
 
@@ -308,13 +309,14 @@ export function shimAddTrackRemoveTrackWithNative(window) {
 
   const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
   window.RTCPeerConnection.prototype.addTrack =
-    function addTrack(track, stream) {
+    function addTrack(track, ...args) {
+      const stream = args[0];
       if (!stream) {
-        return origAddTrack.apply(this, arguments);
+        return origAddTrack.apply(this, [track, ...args]);
       }
       this._shimmedLocalStreams = this._shimmedLocalStreams || {};
 
-      const sender = origAddTrack.apply(this, arguments);
+      const sender = origAddTrack.apply(this, [track, ...args]);
       if (!this._shimmedLocalStreams[stream.id]) {
         this._shimmedLocalStreams[stream.id] = [stream, sender];
       } else if (this._shimmedLocalStreams[stream.id].indexOf(sender) === -1) {
@@ -324,34 +326,35 @@ export function shimAddTrackRemoveTrackWithNative(window) {
     };
 
   const origAddStream = window.RTCPeerConnection.prototype.addStream;
-  window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
-    this._shimmedLocalStreams = this._shimmedLocalStreams || {};
+  window.RTCPeerConnection.prototype.addStream =
+    function addStream(stream, ...args) {
+      this._shimmedLocalStreams = this._shimmedLocalStreams || {};
 
-    stream.getTracks().forEach(track => {
-      const alreadyExists = this.getSenders().find(s => s.track === track);
-      if (alreadyExists) {
-        throw new DOMException('Track already exists.',
-          'InvalidAccessError');
-      }
-    });
-    const existingSenders = this.getSenders();
-    origAddStream.apply(this, arguments);
-    const newSenders = this.getSenders()
-      .filter(newSender => existingSenders.indexOf(newSender) === -1);
-    this._shimmedLocalStreams[stream.id] = [stream].concat(newSenders);
-  };
+      stream.getTracks().forEach(track => {
+        const alreadyExists = this.getSenders().find(s => s.track === track);
+        if (alreadyExists) {
+          throw new DOMException('Track already exists.',
+            'InvalidAccessError');
+        }
+      });
+      const existingSenders = this.getSenders();
+      origAddStream.apply(this, [stream, ...args]);
+      const newSenders = this.getSenders()
+        .filter(newSender => existingSenders.indexOf(newSender) === -1);
+      this._shimmedLocalStreams[stream.id] = [stream].concat(newSenders);
+    };
 
   const origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
   window.RTCPeerConnection.prototype.removeStream =
-    function removeStream(stream) {
+    function removeStream(stream, ...args) {
       this._shimmedLocalStreams = this._shimmedLocalStreams || {};
       delete this._shimmedLocalStreams[stream.id];
-      return origRemoveStream.apply(this, arguments);
+      return origRemoveStream.apply(this, [stream, ...args]);
     };
 
   const origRemoveTrack = window.RTCPeerConnection.prototype.removeTrack;
   window.RTCPeerConnection.prototype.removeTrack =
-    function removeTrack(sender) {
+    function removeTrack(sender, ...args) {
       this._shimmedLocalStreams = this._shimmedLocalStreams || {};
       if (sender) {
         Object.keys(this._shimmedLocalStreams).forEach(streamId => {
@@ -364,7 +367,7 @@ export function shimAddTrackRemoveTrackWithNative(window) {
           }
         });
       }
-      return origRemoveTrack.apply(this, arguments);
+      return origRemoveTrack.apply(this, [sender, ...args]);
     };
 }
 
@@ -390,48 +393,49 @@ export function shimAddTrackRemoveTrack(window, browserDetails) {
     };
 
   const origAddStream = window.RTCPeerConnection.prototype.addStream;
-  window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
-    this._streams = this._streams || {};
-    this._reverseStreams = this._reverseStreams || {};
+  window.RTCPeerConnection.prototype.addStream =
+      function addStream(stream, ...args) {
+        this._streams = this._streams || {};
+        this._reverseStreams = this._reverseStreams || {};
 
-    stream.getTracks().forEach(track => {
-      const alreadyExists = this.getSenders().find(s => s.track === track);
-      if (alreadyExists) {
-        throw new DOMException('Track already exists.',
-          'InvalidAccessError');
-      }
-    });
-    // Add identity mapping for consistency with addTrack.
-    // Unless this is being used with a stream from addTrack.
-    if (!this._reverseStreams[stream.id]) {
-      const newStream = new window.MediaStream(stream.getTracks());
-      this._streams[stream.id] = newStream;
-      this._reverseStreams[newStream.id] = stream;
-      stream = newStream;
-    }
-    origAddStream.apply(this, [stream]);
-  };
+        stream.getTracks().forEach(track => {
+          const alreadyExists = this.getSenders().find(s => s.track === track);
+          if (alreadyExists) {
+            throw new DOMException('Track already exists.',
+              'InvalidAccessError');
+          }
+        });
+        // Add identity mapping for consistency with addTrack.
+        // Unless this is being used with a stream from addTrack.
+        if (!this._reverseStreams[stream.id]) {
+          const newStream = new window.MediaStream(stream.getTracks());
+          this._streams[stream.id] = newStream;
+          this._reverseStreams[newStream.id] = stream;
+          stream = newStream;
+        }
+        origAddStream.apply(this, [stream, ...args]);
+      };
 
   const origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
   window.RTCPeerConnection.prototype.removeStream =
-    function removeStream(stream) {
+    function removeStream(stream, ...args) {
       this._streams = this._streams || {};
       this._reverseStreams = this._reverseStreams || {};
 
-      origRemoveStream.apply(this, [(this._streams[stream.id] || stream)]);
+      origRemoveStream.apply(this, [(this._streams[stream.id] || stream),
+        ...args]);
       delete this._reverseStreams[(this._streams[stream.id] ?
         this._streams[stream.id].id : stream.id)];
       delete this._streams[stream.id];
     };
 
   window.RTCPeerConnection.prototype.addTrack =
-    function addTrack(track, stream) {
+    function addTrack(track, ...streams) {
       if (this.signalingState === 'closed') {
         throw new DOMException(
           'The RTCPeerConnection\'s signalingState is \'closed\'.',
           'InvalidStateError');
       }
-      const streams = [].slice.call(arguments, 1);
       if (streams.length !== 1 ||
           !streams[0].getTracks().find(t => t === track)) {
         // this is not fully correct but all we can manage without
@@ -450,6 +454,7 @@ export function shimAddTrackRemoveTrack(window, browserDetails) {
 
       this._streams = this._streams || {};
       this._reverseStreams = this._reverseStreams || {};
+      const stream = streams[0];
       const oldStream = this._streams[stream.id];
       if (oldStream) {
         // this is using odd Chrome behaviour, use with caution:
@@ -501,10 +506,9 @@ export function shimAddTrackRemoveTrack(window, browserDetails) {
   }
   ['createOffer', 'createAnswer'].forEach(function(method) {
     const nativeMethod = window.RTCPeerConnection.prototype[method];
-    const methodObj = {[method]() {
-      const args = arguments;
-      const isLegacyCall = arguments.length &&
-          typeof arguments[0] === 'function';
+    const methodObj = {[method](...args) {
+      const isLegacyCall = args.length &&
+          typeof args[0] === 'function';
       if (isLegacyCall) {
         return nativeMethod.apply(this, [
           (description) => {
@@ -515,10 +519,10 @@ export function shimAddTrackRemoveTrack(window, browserDetails) {
             if (args[1]) {
               args[1].apply(null, err);
             }
-          }, arguments[2]
+          }, args[2]
         ]);
       }
-      return nativeMethod.apply(this, arguments)
+      return nativeMethod.apply(this, args)
         .then(description => replaceInternalStreamId(this, description));
     }};
     window.RTCPeerConnection.prototype[method] = methodObj[method];
@@ -527,12 +531,14 @@ export function shimAddTrackRemoveTrack(window, browserDetails) {
   const origSetLocalDescription =
       window.RTCPeerConnection.prototype.setLocalDescription;
   window.RTCPeerConnection.prototype.setLocalDescription =
-    function setLocalDescription() {
-      if (!arguments.length || !arguments[0].type) {
-        return origSetLocalDescription.apply(this, arguments);
+    function setLocalDescription(...args) {
+      let description = args[0];
+      if (!args.length || !description.type) {
+        return origSetLocalDescription.apply(this, args);
       }
-      arguments[0] = replaceExternalStreamId(this, arguments[0]);
-      return origSetLocalDescription.apply(this, arguments);
+      description = replaceExternalStreamId(this, description);
+      return origSetLocalDescription.apply(this, [description,
+        ...args.slice(1)]);
     };
 
   // TODO: mangle getStats: https://w3c.github.io/webrtc-stats/#dom-rtcmediastreamstats-streamidentifier
@@ -608,11 +614,12 @@ export function shimPeerConnection(window, browserDetails) {
     ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
       .forEach(function(method) {
         const nativeMethod = window.RTCPeerConnection.prototype[method];
-        const methodObj = {[method]() {
-          arguments[0] = new ((method === 'addIceCandidate') ?
+        const methodObj = {[method](...args) {
+          let description = args[0];
+          description = new ((method === 'addIceCandidate') ?
             window.RTCIceCandidate :
-            window.RTCSessionDescription)(arguments[0]);
-          return nativeMethod.apply(this, arguments);
+            window.RTCSessionDescription)(description);
+          return nativeMethod.apply(this, [description, ...args.slice(1)]);
         }};
         window.RTCPeerConnection.prototype[method] = methodObj[method];
       });
diff --git a/src/js/common_shim.js b/src/js/common_shim.js
index bff69706..db70e724 100644
--- a/src/js/common_shim.js
+++ b/src/js/common_shim.js
@@ -191,7 +191,7 @@ export function shimMaxMessageSize(window, browserDetails) {
   const origSetRemoteDescription =
       window.RTCPeerConnection.prototype.setRemoteDescription;
   window.RTCPeerConnection.prototype.setRemoteDescription =
-    function setRemoteDescription() {
+    function setRemoteDescription(description, ...args) {
       this._sctp = null;
       // Chrome decided to not expose .sctp in plan-b mode.
       // As usual, adapter.js has to do an 'ugly worakaround'
@@ -209,15 +209,15 @@ export function shimMaxMessageSize(window, browserDetails) {
         }
       }
 
-      if (sctpInDescription(arguments[0])) {
+      if (sctpInDescription(description)) {
         // Check if the remote is FF.
-        const isFirefox = getRemoteFirefoxVersion(arguments[0]);
+        const isFirefox = getRemoteFirefoxVersion(description);
 
         // Get the maximum message size the local peer is capable of sending
         const canSendMMS = getCanSendMaxMessageSize(isFirefox);
 
         // Get the maximum message size of the remote peer.
-        const remoteMMS = getMaxMessageSize(arguments[0], isFirefox);
+        const remoteMMS = getMaxMessageSize(description, isFirefox);
 
         // Determine final maximum message size
         let maxMessageSize;
@@ -240,7 +240,7 @@ export function shimMaxMessageSize(window, browserDetails) {
         this._sctp = sctp;
       }
 
-      return origSetRemoteDescription.apply(this, arguments);
+      return origSetRemoteDescription.apply(this, [description, ...args]);
     };
 }
 
@@ -256,22 +256,21 @@ export function shimSendThrowTypeError(window) {
 
   function wrapDcSend(dc, pc) {
     const origDataChannelSend = dc.send;
-    dc.send = function send() {
-      const data = arguments[0];
+    dc.send = function send(data, ...args) {
       const length = data.length || data.size || data.byteLength;
       if (dc.readyState === 'open' &&
           pc.sctp && length > pc.sctp.maxMessageSize) {
         throw new TypeError('Message too large (can send a maximum of ' +
           pc.sctp.maxMessageSize + ' bytes)');
       }
-      return origDataChannelSend.apply(dc, arguments);
+      return origDataChannelSend.apply(dc, [data, ...args]);
     };
   }
   const origCreateDataChannel =
     window.RTCPeerConnection.prototype.createDataChannel;
   window.RTCPeerConnection.prototype.createDataChannel =
-    function createDataChannel() {
-      const dataChannel = origCreateDataChannel.apply(this, arguments);
+    function createDataChannel(label, ...args) {
+      const dataChannel = origCreateDataChannel.apply(this, [label, ...args]);
       wrapDcSend(dataChannel, this);
       return dataChannel;
     };
@@ -326,7 +325,7 @@ export function shimConnectionState(window) {
 
   ['setLocalDescription', 'setRemoteDescription'].forEach((method) => {
     const origMethod = proto[method];
-    proto[method] = function() {
+    proto[method] = function(...args) {
       if (!this._connectionstatechangepoly) {
         this._connectionstatechangepoly = e => {
           const pc = e.target;
@@ -340,7 +339,7 @@ export function shimConnectionState(window) {
         this.addEventListener('iceconnectionstatechange',
           this._connectionstatechangepoly);
       }
-      return origMethod.apply(this, arguments);
+      return origMethod.apply(this, args);
     };
   });
 }
@@ -359,23 +358,24 @@ export function removeExtmapAllowMixed(window, browserDetails) {
   }
   const nativeSRD = window.RTCPeerConnection.prototype.setRemoteDescription;
   window.RTCPeerConnection.prototype.setRemoteDescription =
-  function setRemoteDescription(desc) {
-    if (desc && desc.sdp && desc.sdp.indexOf('\na=extmap-allow-mixed') !== -1) {
-      const sdp = desc.sdp.split('\n').filter((line) => {
+  function setRemoteDescription(description, ...args) {
+    if (description && description.sdp &&
+        description.sdp.indexOf('\na=extmap-allow-mixed') !== -1) {
+      const sdp = description.sdp.split('\n').filter((line) => {
         return line.trim() !== 'a=extmap-allow-mixed';
       }).join('\n');
       // Safari enforces read-only-ness of RTCSessionDescription fields.
       if (window.RTCSessionDescription &&
-          desc instanceof window.RTCSessionDescription) {
-        arguments[0] = new window.RTCSessionDescription({
-          type: desc.type,
+          description instanceof window.RTCSessionDescription) {
+        description = new window.RTCSessionDescription({
+          type: description.type,
           sdp,
         });
       } else {
-        desc.sdp = sdp;
+        description.sdp = sdp;
       }
     }
-    return nativeSRD.apply(this, arguments);
+    return nativeSRD.apply(this, [description, ...args]);
   };
 }
 
@@ -393,10 +393,11 @@ export function shimAddIceCandidateNullOrEmpty(window, browserDetails) {
     return;
   }
   window.RTCPeerConnection.prototype.addIceCandidate =
-    function addIceCandidate() {
-      if (!arguments[0]) {
-        if (arguments[1]) {
-          arguments[1].apply(null);
+    function addIceCandidate(...args) {
+      const candidate = args[0];
+      if (!candidate) {
+        if (args[1]) {
+          args[1].apply(null);
         }
         return Promise.resolve();
       }
@@ -409,10 +410,10 @@ export function shimAddIceCandidateNullOrEmpty(window, browserDetails) {
            || (browserDetails.browser === 'firefox'
                && browserDetails.version < 68)
            || (browserDetails.browser === 'safari'))
-          && arguments[0] && arguments[0].candidate === '') {
+          && candidate && candidate.candidate === '') {
         return Promise.resolve();
       }
-      return nativeAddIceCandidate.apply(this, arguments);
+      return nativeAddIceCandidate.apply(this, args);
     };
 }
 
@@ -428,10 +429,10 @@ export function shimParameterlessSetLocalDescription(window, browserDetails) {
     return;
   }
   window.RTCPeerConnection.prototype.setLocalDescription =
-    function setLocalDescription() {
-      let desc = arguments[0] || {};
+    function setLocalDescription(...args) {
+      let desc = args[0] || {};
       if (typeof desc !== 'object' || (desc.type && desc.sdp)) {
-        return nativeSetLocalDescription.apply(this, arguments);
+        return nativeSetLocalDescription.apply(this, args);
       }
       // The remaining steps should technically happen when SLD comes off the
       // RTCPeerConnection's operations chain (not ahead of going on it), but
diff --git a/src/js/firefox/firefox_shim.js b/src/js/firefox/firefox_shim.js
index 4b9852b8..6598a352 100644
--- a/src/js/firefox/firefox_shim.js
+++ b/src/js/firefox/firefox_shim.js
@@ -39,11 +39,12 @@ export function shimPeerConnection(window, browserDetails) {
     ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
       .forEach(function(method) {
         const nativeMethod = window.RTCPeerConnection.prototype[method];
-        const methodObj = {[method]() {
-          arguments[0] = new ((method === 'addIceCandidate') ?
+        const methodObj = {[method](...args) {
+          let description = args[0];
+          description = new ((method === 'addIceCandidate') ?
             window.RTCIceCandidate :
-            window.RTCSessionDescription)(arguments[0]);
-          return nativeMethod.apply(this, arguments);
+            window.RTCSessionDescription)(description);
+          return nativeMethod.apply(this, [description, ...args.slice(1)]);
         }};
         window.RTCPeerConnection.prototype[method] = methodObj[method];
       });
@@ -58,8 +59,8 @@ export function shimPeerConnection(window, browserDetails) {
   };
 
   const nativeGetStats = window.RTCPeerConnection.prototype.getStats;
-  window.RTCPeerConnection.prototype.getStats = function getStats() {
-    const [selector, onSucc, onErr] = arguments;
+  window.RTCPeerConnection.prototype.getStats = function getStats(...args) {
+    const [selector, onSucc, onErr] = args;
     return nativeGetStats.apply(this, [selector || null])
       .then(stats => {
         if (browserDetails.version < 53 && !onSucc) {
@@ -106,11 +107,12 @@ export function shimSenderGetStats(window) {
 
   const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
   if (origAddTrack) {
-    window.RTCPeerConnection.prototype.addTrack = function addTrack() {
-      const sender = origAddTrack.apply(this, arguments);
-      sender._pc = this;
-      return sender;
-    };
+    window.RTCPeerConnection.prototype.addTrack =
+      function addTrack(track, ...args) {
+        const sender = origAddTrack.apply(this, [track, ...args]);
+        sender._pc = this;
+        return sender;
+      };
   }
   window.RTCRtpSender.prototype.getStats = function getStats() {
     return this.track ? this._pc.getStats(this.track) :
@@ -177,10 +179,10 @@ export function shimAddTransceiver(window) {
   const origAddTransceiver = window.RTCPeerConnection.prototype.addTransceiver;
   if (origAddTransceiver) {
     window.RTCPeerConnection.prototype.addTransceiver =
-      function addTransceiver() {
+      function addTransceiver(trackOrKind, ...args) {
         this.setParametersPromises = [];
         // WebIDL input coercion and validation
-        let sendEncodings = arguments[1] && arguments[1].sendEncodings;
+        let sendEncodings = args[0] && args[0].sendEncodings;
         if (sendEncodings === undefined) {
           sendEncodings = [];
         }
@@ -207,7 +209,8 @@ export function shimAddTransceiver(window) {
             }
           });
         }
-        const transceiver = origAddTransceiver.apply(this, arguments);
+        const transceiver = origAddTransceiver.apply(this,
+          [trackOrKind, ...args]);
         if (shouldPerformCheck) {
           // Check if the init options were applied. If not we do this in an
           // asynchronous way and save the promise reference in a global object.
@@ -245,8 +248,8 @@ export function shimGetParameters(window) {
   const origGetParameters = window.RTCRtpSender.prototype.getParameters;
   if (origGetParameters) {
     window.RTCRtpSender.prototype.getParameters =
-      function getParameters() {
-        const params = origGetParameters.apply(this, arguments);
+      function getParameters(...args) {
+        const params = origGetParameters.apply(this, args);
         if (!('encodings' in params)) {
           params.encodings = [].concat(this.sendEncodings || [{}]);
         }
@@ -263,18 +266,19 @@ export function shimCreateOffer(window) {
     return;
   }
   const origCreateOffer = window.RTCPeerConnection.prototype.createOffer;
-  window.RTCPeerConnection.prototype.createOffer = function createOffer() {
-    if (this.setParametersPromises && this.setParametersPromises.length) {
-      return Promise.all(this.setParametersPromises)
-        .then(() => {
-          return origCreateOffer.apply(this, arguments);
-        })
-        .finally(() => {
-          this.setParametersPromises = [];
-        });
-    }
-    return origCreateOffer.apply(this, arguments);
-  };
+  window.RTCPeerConnection.prototype.createOffer =
+    function createOffer(...args) {
+      if (this.setParametersPromises && this.setParametersPromises.length) {
+        return Promise.all(this.setParametersPromises)
+          .then(() => {
+            return origCreateOffer.apply(this, args);
+          })
+          .finally(() => {
+            this.setParametersPromises = [];
+          });
+      }
+      return origCreateOffer.apply(this, args);
+    };
 }
 
 export function shimCreateAnswer(window) {
@@ -285,16 +289,17 @@ export function shimCreateAnswer(window) {
     return;
   }
   const origCreateAnswer = window.RTCPeerConnection.prototype.createAnswer;
-  window.RTCPeerConnection.prototype.createAnswer = function createAnswer() {
-    if (this.setParametersPromises && this.setParametersPromises.length) {
-      return Promise.all(this.setParametersPromises)
-        .then(() => {
-          return origCreateAnswer.apply(this, arguments);
-        })
-        .finally(() => {
-          this.setParametersPromises = [];
-        });
-    }
-    return origCreateAnswer.apply(this, arguments);
-  };
+  window.RTCPeerConnection.prototype.createAnswer =
+    function createAnswer(...args) {
+      if (this.setParametersPromises && this.setParametersPromises.length) {
+        return Promise.all(this.setParametersPromises)
+          .then(() => {
+            return origCreateAnswer.apply(this, args);
+          })
+          .finally(() => {
+            this.setParametersPromises = [];
+          });
+      }
+      return origCreateAnswer.apply(this, args);
+    };
 }
diff --git a/src/js/firefox/getusermedia.js b/src/js/firefox/getusermedia.js
index 6b7d87b7..24921190 100644
--- a/src/js/firefox/getusermedia.js
+++ b/src/js/firefox/getusermedia.js
@@ -43,8 +43,8 @@ export function shimGetUserMedia(window, browserDetails) {
 
     if (MediaStreamTrack && MediaStreamTrack.prototype.getSettings) {
       const nativeGetSettings = MediaStreamTrack.prototype.getSettings;
-      MediaStreamTrack.prototype.getSettings = function() {
-        const obj = nativeGetSettings.apply(this, arguments);
+      MediaStreamTrack.prototype.getSettings = function(...args) {
+        const obj = nativeGetSettings.apply(this, args);
         remap(obj, 'mozAutoGainControl', 'autoGainControl');
         remap(obj, 'mozNoiseSuppression', 'noiseSuppression');
         return obj;
diff --git a/src/js/safari/safari_shim.js b/src/js/safari/safari_shim.js
index cfd09a33..73b09647 100644
--- a/src/js/safari/safari_shim.js
+++ b/src/js/safari/safari_shim.js
@@ -49,7 +49,7 @@ export function shimLocalStreamsAPI(window) {
             }
           });
         }
-        return _addTrack.apply(this, arguments);
+        return _addTrack.apply(this, [track, ...streams]);
       };
   }
   if (!('removeStream' in window.RTCPeerConnection.prototype)) {
@@ -113,7 +113,7 @@ export function shimRemoteStreamsAPI(window) {
     const origSetRemoteDescription =
       window.RTCPeerConnection.prototype.setRemoteDescription;
     window.RTCPeerConnection.prototype.setRemoteDescription =
-      function setRemoteDescription() {
+      function setRemoteDescription(description, ...args) {
         const pc = this;
         if (!this._onaddstreampoly) {
           this.addEventListener('track', this._onaddstreampoly = function(e) {
@@ -131,7 +131,7 @@ export function shimRemoteStreamsAPI(window) {
             });
           });
         }
-        return origSetRemoteDescription.apply(pc, arguments);
+        return origSetRemoteDescription.apply(pc, [description, ...args]);
       };
   }
 }
@@ -140,16 +140,13 @@ export function shimCallbacksAPI(window) {
   if (typeof window !== 'object' || !window.RTCPeerConnection) {
     return;
   }
-  const prototype = window.RTCPeerConnection.prototype;
-  const origCreateOffer = prototype.createOffer;
-  const origCreateAnswer = prototype.createAnswer;
-  const setLocalDescription = prototype.setLocalDescription;
-  const setRemoteDescription = prototype.setRemoteDescription;
-  const addIceCandidate = prototype.addIceCandidate;
 
-  prototype.createOffer =
-    function createOffer(successCallback, failureCallback) {
-      const options = (arguments.length >= 2) ? arguments[2] : arguments[0];
+  const origCreateOffer = window.RTCPeerConnection.prototype.createOffer;
+  window.RTCPeerConnection.prototype.createOffer =
+    function createOffer(...args) {
+      const successCallback = args[0];
+      const failureCallback = args[1];
+      const options = (args.length >= 2) ? args[2] : args[0];
       const promise = origCreateOffer.apply(this, [options]);
       if (!failureCallback) {
         return promise;
@@ -158,9 +155,12 @@ export function shimCallbacksAPI(window) {
       return Promise.resolve();
     };
 
-  prototype.createAnswer =
-    function createAnswer(successCallback, failureCallback) {
-      const options = (arguments.length >= 2) ? arguments[2] : arguments[0];
+  const origCreateAnswer = window.RTCPeerConnection.prototype.createAnswer;
+  window.RTCPeerConnection.prototype.createAnswer =
+    function createAnswer(...args) {
+      const successCallback = args[0];
+      const failureCallback = args[1];
+      const options = (args.length >= 2) ? args[2] : args[0];
       const promise = origCreateAnswer.apply(this, [options]);
       if (!failureCallback) {
         return promise;
@@ -169,35 +169,43 @@ export function shimCallbacksAPI(window) {
       return Promise.resolve();
     };
 
-  let withCallback = function(description, successCallback, failureCallback) {
-    const promise = setLocalDescription.apply(this, [description]);
-    if (!failureCallback) {
-      return promise;
-    }
-    promise.then(successCallback, failureCallback);
-    return Promise.resolve();
-  };
-  prototype.setLocalDescription = withCallback;
+  const origSetLocalDescription =
+    window.RTCPeerConnection.prototype.setLocalDescription;
+  window.RTCPeerConnection.prototype.setLocalDescription =
+    function(...args) {
+      const [description, successCallback, failureCallback] = args;
+      const promise = origSetLocalDescription.apply(this, [description]);
+      if (!failureCallback) {
+        return promise;
+      }
+      promise.then(successCallback, failureCallback);
+      return Promise.resolve();
+    };
 
-  withCallback = function(description, successCallback, failureCallback) {
-    const promise = setRemoteDescription.apply(this, [description]);
-    if (!failureCallback) {
-      return promise;
-    }
-    promise.then(successCallback, failureCallback);
-    return Promise.resolve();
-  };
-  prototype.setRemoteDescription = withCallback;
+  const origSetRemoteDescription =
+    window.RTCPeerConnection.prototype.setRemoteDescription;
+  window.RTCPeerConnection.prototype.setRemoteDescription =
+    function(description, ...args) {
+      const [successCallback, failureCallback] = args;
+      const promise = origSetRemoteDescription.apply(this, [description]);
+      if (!failureCallback) {
+        return promise;
+      }
+      promise.then(successCallback, failureCallback);
+      return Promise.resolve();
+    };
 
-  withCallback = function(candidate, successCallback, failureCallback) {
-    const promise = addIceCandidate.apply(this, [candidate]);
+  const origAddIceCandidate =
+    window.RTCPeerConnection.prototype.addIceCandidate;
+  window.RTCPeerConnection.prototype.addIceCandidate = function(...args) {
+    const [candidate, successCallback, failureCallback] = args;
+    const promise = origAddIceCandidate.apply(this, [candidate]);
     if (!failureCallback) {
       return promise;
     }
     promise.then(successCallback, failureCallback);
     return Promise.resolve();
   };
-  prototype.addIceCandidate = withCallback;
 }
 
 export function shimGetUserMedia(window) {
@@ -239,11 +247,11 @@ export function shimRTCIceServerUrls(window) {
   // migrate from non-spec RTCIceServer.url to RTCIceServer.urls
   const OrigPeerConnection = window.RTCPeerConnection;
   window.RTCPeerConnection =
-    function RTCPeerConnection(pcConfig, pcConstraints) {
-      if (pcConfig && pcConfig.iceServers) {
+    function RTCPeerConnection(config, ...args) {
+      if (config && config.iceServers) {
         const newIceServers = [];
-        for (let i = 0; i < pcConfig.iceServers.length; i++) {
-          let server = pcConfig.iceServers[i];
+        for (let i = 0; i < config.iceServers.length; i++) {
+          let server = config.iceServers[i];
           if (server.urls === undefined && server.url) {
             utils.deprecated('RTCIceServer.url', 'RTCIceServer.urls');
             server = JSON.parse(JSON.stringify(server));
@@ -251,12 +259,12 @@ export function shimRTCIceServerUrls(window) {
             delete server.url;
             newIceServers.push(server);
           } else {
-            newIceServers.push(pcConfig.iceServers[i]);
+            newIceServers.push(config.iceServers[i]);
           }
         }
-        pcConfig.iceServers = newIceServers;
+        config.iceServers = newIceServers;
       }
-      return new OrigPeerConnection(pcConfig, pcConstraints);
+      return new OrigPeerConnection(config, [...args]);
     };
   window.RTCPeerConnection.prototype = OrigPeerConnection.prototype;
   // wrap static methods. Currently just generateCertificate.
@@ -285,7 +293,8 @@ export function shimTrackEventTransceiver(window) {
 export function shimCreateOfferLegacy(window) {
   const origCreateOffer = window.RTCPeerConnection.prototype.createOffer;
   window.RTCPeerConnection.prototype.createOffer =
-    function createOffer(offerOptions) {
+    function createOffer(...args) {
+      const offerOptions = args[0];
       if (offerOptions) {
         if (typeof offerOptions.offerToReceiveAudio !== 'undefined') {
           // support bit values
@@ -339,7 +348,7 @@ export function shimCreateOfferLegacy(window) {
           this.addTransceiver('video', {direction: 'recvonly'});
         }
       }
-      return origCreateOffer.apply(this, arguments);
+      return origCreateOffer.apply(this, args);
     };
 }
 
diff --git a/src/js/utils.js b/src/js/utils.js
index 11bb46f0..d6f4ce12 100644
--- a/src/js/utils.js
+++ b/src/js/utils.js
@@ -33,9 +33,9 @@ export function wrapPeerConnectionEvent(window, eventNameToWrap, wrapper) {
   }
   const proto = window.RTCPeerConnection.prototype;
   const nativeAddEventListener = proto.addEventListener;
-  proto.addEventListener = function(nativeEventName, cb) {
+  proto.addEventListener = function(nativeEventName, cb, ...args) {
     if (nativeEventName !== eventNameToWrap) {
-      return nativeAddEventListener.apply(this, arguments);
+      return nativeAddEventListener.apply(this, [nativeEventName, cb, ...args]);
     }
     const wrappedCallback = (e) => {
       const modifiedEvent = wrapper(e);
@@ -53,17 +53,19 @@ export function wrapPeerConnectionEvent(window, eventNameToWrap, wrapper) {
     }
     this._eventMap[eventNameToWrap].set(cb, wrappedCallback);
     return nativeAddEventListener.apply(this, [nativeEventName,
-      wrappedCallback]);
+      wrappedCallback, ...args]);
   };
 
   const nativeRemoveEventListener = proto.removeEventListener;
-  proto.removeEventListener = function(nativeEventName, cb) {
+  proto.removeEventListener = function(nativeEventName, cb, ...args) {
     if (nativeEventName !== eventNameToWrap || !this._eventMap
         || !this._eventMap[eventNameToWrap]) {
-      return nativeRemoveEventListener.apply(this, arguments);
+      return nativeRemoveEventListener.apply(this, [nativeEventName, cb,
+        ...args]);
     }
     if (!this._eventMap[eventNameToWrap].has(cb)) {
-      return nativeRemoveEventListener.apply(this, arguments);
+      return nativeRemoveEventListener.apply(this, [nativeEventName, cb,
+        ...args]);
     }
     const unwrappedCb = this._eventMap[eventNameToWrap].get(cb);
     this._eventMap[eventNameToWrap].delete(cb);
@@ -74,7 +76,7 @@ export function wrapPeerConnectionEvent(window, eventNameToWrap, wrapper) {
       delete this._eventMap;
     }
     return nativeRemoveEventListener.apply(this, [nativeEventName,
-      unwrappedCb]);
+      unwrappedCb, ...args]);
   };
 
   Object.defineProperty(proto, 'on' + eventNameToWrap, {
@@ -120,13 +122,13 @@ export function disableWarnings(bool) {
   return 'adapter.js deprecation warnings ' + (bool ? 'disabled' : 'enabled');
 }
 
-export function log() {
+export function log(...args) {
   if (typeof window === 'object') {
     if (logDisabled_) {
       return;
     }
     if (typeof console !== 'undefined' && typeof console.log === 'function') {
-      console.log.apply(console, arguments);
+      console.log(...args);
     }
   }
 }
diff --git a/test/e2e/rtcpeerconnection.js b/test/e2e/rtcpeerconnection.js
index 811a1f37..0762e071 100644
--- a/test/e2e/rtcpeerconnection.js
+++ b/test/e2e/rtcpeerconnection.js
@@ -61,4 +61,38 @@ describe('RTCPeerConnection', () => {
         .then(offer => pc.setLocalDescription(offer));
     });
   });
+
+  it('has the correct number of arguments for shimmed methods', () => {
+    // createOffer(optional RTCOfferOptions options = {})
+    expect(RTCPeerConnection.prototype.createOffer.length).to.equal(0);
+
+    // createAnswer(optional RTCAnswerOptions options = {})
+    expect(RTCPeerConnection.prototype.createAnswer.length).to.equal(0);
+
+    // setLocalDescription(optional RTCSessionDescriptionInit description = {})
+    expect(RTCPeerConnection.prototype.setLocalDescription.length).to.equal(0);
+
+    // setRemoteDescription(RTCSessionDescriptionInit description)
+    expect(RTCPeerConnection.prototype.setRemoteDescription.length).to.equal(1);
+
+    // addIceCandidate(optional RTCIceCandidateInit candidate = {})
+    expect(RTCPeerConnection.prototype.addIceCandidate.length).to.equal(0);
+
+    // getStats(optional MediaStreamTrack? selector = null)
+    expect(RTCPeerConnection.prototype.getStats.length).to.equal(0);
+
+    // addTransceiver((MediaStreamTrack or DOMString) trackOrKind,
+    //   optional RTCRtpTransceiverInit init = {})
+    expect(RTCPeerConnection.prototype.addTransceiver.length).to.equal(1);
+
+    // addTrack(MediaStreamTrack track, MediaStream... streams)
+    expect(RTCPeerConnection.prototype.addTrack.length).to.equal(1);
+
+    // removeTrack(RTCRtpSender sender)
+    expect(RTCPeerConnection.prototype.removeTrack.length).to.equal(1);
+
+    // createDataChannel(USVString label,
+    //   optional RTCDataChannelInit dataChannelDict = {})
+    expect(RTCPeerConnection.prototype.createDataChannel.length).to.equal(1);
+  });
 });
diff --git a/test/unit/safari.test.js b/test/unit/safari.test.js
index d3ca5436..b9cb7a79 100644
--- a/test/unit/safari.test.js
+++ b/test/unit/safari.test.js
@@ -23,12 +23,12 @@ describe('Safari shim', () => {
     });
 
     it('shimStreamsAPI existence', () => {
-      const prototype = window.RTCPeerConnection.prototype;
-      expect(prototype.addTrack.length).toBe(1);
-      expect(prototype.addStream.length).toBe(1);
-      expect(prototype.removeStream.length).toBe(1);
-      expect(prototype.getLocalStreams.length).toBe(0);
-      expect(prototype.getRemoteStreams.length).toBe(0);
+      expect(window.RTCPeerConnection.prototype.addTrack.length).toBe(1);
+      expect(window.RTCPeerConnection.prototype.addStream.length).toBe(1);
+      expect(window.RTCPeerConnection.prototype.removeStream.length).toBe(1);
+      expect(window.RTCPeerConnection.prototype.getLocalStreams.length).toBe(0);
+      expect(window.RTCPeerConnection.prototype.getRemoteStreams.length)
+        .toBe(0);
     });
     it('local streams API', () => {
       const pc = new window.RTCPeerConnection();
@@ -72,12 +72,13 @@ describe('Safari shim', () => {
   describe('shimCallbacksAPI', () => {
     it('shimCallbacksAPI existence', () => {
       shim.shimCallbacksAPI(window);
-      const prototype = window.RTCPeerConnection.prototype;
-      expect(prototype.createOffer.length).toBe(2);
-      expect(prototype.createAnswer.length).toBe(2);
-      expect(prototype.setLocalDescription.length).toBe(3);
-      expect(prototype.setRemoteDescription.length).toBe(3);
-      expect(prototype.addIceCandidate.length).toBe(3);
+      expect(window.RTCPeerConnection.prototype.createOffer.length).toBe(0);
+      expect(window.RTCPeerConnection.prototype.createAnswer.length).toBe(0);
+      expect(window.RTCPeerConnection.prototype.setLocalDescription.length)
+        .toBe(0);
+      expect(window.RTCPeerConnection.prototype.setRemoteDescription.length)
+        .toBe(1);
+      expect(window.RTCPeerConnection.prototype.addIceCandidate.length).toBe(0);
     });
   });