--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -1100,19 +1100,18 @@ nsContentUtils::ParseHTMLInteger(const n
 
   while (iter != end) {
     if (*iter >= char16_t('0') && *iter <= char16_t('9')) {
       value = (value * 10) + (*iter - char16_t('0')) * sign;
       ++iter;
       if (!value.isValid()) {
         result |= eParseHTMLInteger_Error | eParseHTMLInteger_ErrorOverflow;
         break;
-      } else {
-        foundValue = true;
       }
+      foundValue = true;
     } else if (*iter == char16_t('%')) {
       ++iter;
       result |= eParseHTMLInteger_IsPercent;
       break;
     } else {
       break;
     }
   }
@@ -4937,32 +4936,30 @@ bool
 nsContentUtils::AppendNodeTextContent(nsINode* aNode, bool aDeep,
                                       nsAString& aResult,
                                       const fallible_t& aFallible)
 {
   if (aNode->IsNodeOfType(nsINode::eTEXT)) {
     return static_cast<nsIContent*>(aNode)->AppendTextTo(aResult,
                                                          aFallible);
   }
-  else if (aDeep) {
+  if (aDeep) {
     return AppendNodeTextContentsRecurse(aNode, aResult, aFallible);
   }
-  else {
-    for (nsIContent* child = aNode->GetFirstChild();
-         child;
-         child = child->GetNextSibling()) {
-      if (child->IsNodeOfType(nsINode::eTEXT)) {
-        bool ok = child->AppendTextTo(aResult, fallible);
-        if (!ok) {
-            return false;
-        }
+
+  for (nsIContent* child = aNode->GetFirstChild();
+       child;
+       child = child->GetNextSibling()) {
+    if (child->IsNodeOfType(nsINode::eTEXT)) {
+      bool ok = child->AppendTextTo(aResult, fallible);
+      if (!ok) {
+        return false;
       }
     }
   }
-
   return true;
 }
 
 bool
 nsContentUtils::HasNonEmptyTextContent(nsINode* aNode,
                                        TextContentDiscoverMode aDiscoverMode)
 {
   for (nsIContent* child = aNode->GetFirstChild();
@@ -5751,19 +5748,18 @@ nsContentUtils::GetCurrentJSContext()
 
 /* static */
 JSContext *
 nsContentUtils::GetCurrentJSContextForThread()
 {
   MOZ_ASSERT(IsInitialized());
   if (MOZ_LIKELY(NS_IsMainThread())) {
     return GetCurrentJSContext();
-  } else {
-    return workers::GetCurrentThreadJSContext();
-  }
+  }
+  return workers::GetCurrentThreadJSContext();
 }
 
 template<typename StringType, typename CharType>
 void
 _ASCIIToLowerInSitu(StringType& aStr)
 {
   CharType* iter = aStr.BeginWriting();
   CharType* end = aStr.EndWriting();
@@ -8685,19 +8681,21 @@ nsContentUtils::InternalStorageAllowedFo
   }
 
   // check the permission manager for any allow or deny permissions
   // for cookies for the window.
   uint32_t perm;
   permissionManager->TestPermissionFromPrincipal(aPrincipal, "cookie", &perm);
   if (perm == nsIPermissionManager::DENY_ACTION) {
     return StorageAccess::eDeny;
-  } else if (perm == nsICookiePermission::ACCESS_SESSION) {
+  }
+  if (perm == nsICookiePermission::ACCESS_SESSION) {
     return std::min(access, StorageAccess::eSessionScoped);
-  } else if (perm == nsIPermissionManager::ALLOW_ACTION) {
+  }
+  if (perm == nsIPermissionManager::ALLOW_ACTION) {
     return access;
   }
 
   // Check if we should only allow storage for the session, and record that fact
   if (sCookiesLifetimePolicy == nsICookieService::ACCEPT_SESSION) {
     // Storage could be StorageAccess::ePrivateBrowsing or StorageAccess::eAllow
     // so perform a std::min comparison to make sure we preserve ePrivateBrowsing
     // if it has been set.

--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -3702,20 +3702,18 @@ nsDOMWindowUtils::GetOMTAStyle(nsIDOMEle
   }
 
   if (cssValue) {
     nsString text;
     ErrorResult rv;
     cssValue->GetCssText(text, rv);
     aResult.Assign(text);
     return rv.StealNSResult();
-  } else {
-    aResult.Truncate();
   }
-
+  aResult.Truncate();
   return NS_OK;
 }
 
 namespace {
 
 class HandlingUserInputHelper final : public nsIJSRAIIHelper
 {
 public:

--- a/dom/base/nsFrameMessageManager.cpp
+++ b/dom/base/nsFrameMessageManager.cpp
@@ -797,19 +797,18 @@ nsFrameMessageManager::Dump(const nsAStr
 }
 
 NS_IMETHODIMP
 nsFrameMessageManager::PrivateNoteIntentionalCrash()
 {
   if (XRE_IsContentProcess()) {
     mozilla::NoteIntentionalCrash("tab");
     return NS_OK;
-  } else {
-    return NS_ERROR_NOT_IMPLEMENTED;
   }
+  return NS_ERROR_NOT_IMPLEMENTED;
 }
 
 NS_IMETHODIMP
 nsFrameMessageManager::GetContent(mozIDOMWindowProxy** aContent)
 {
   *aContent = nullptr;
   return NS_OK;
 }

--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -6820,23 +6820,22 @@ MakeWidgetFullscreen(nsGlobalWindow* aWi
     }
   }
   // We pass nullptr as the screen to SetWidgetFullscreen
   // and FullscreenTransitionTask, as we do not wish to override
   // the default screen selection behavior.  The screen containing
   // most of the widget will be selected.
   if (!performTransition) {
     return aWindow->SetWidgetFullscreen(aReason, aFullscreen, widget, nullptr);
-  } else {
-    nsCOMPtr<nsIRunnable> task =
-      new FullscreenTransitionTask(duration, aWindow, aFullscreen,
-                                   widget, nullptr, transitionData);
-    task->Run();
-    return true;
-  }
+  }
+  nsCOMPtr<nsIRunnable> task =
+    new FullscreenTransitionTask(duration, aWindow, aFullscreen,
+                                 widget, nullptr, transitionData);
+  task->Run();
+  return true;
 }
 
 nsresult
 nsGlobalWindow::SetFullscreenInternal(FullscreenReason aReason,
                                       bool aFullScreen)
 {
   MOZ_ASSERT(IsOuterWindow());
   MOZ_ASSERT(nsContentUtils::IsSafeToRunScript(),
@@ -14545,20 +14544,19 @@ nsGlobalWindow::CreateImageBitmap(const 
                                   int32_t aOffset, int32_t aLength,
                                   ImageBitmapFormat aFormat,
                                   const Sequence<ChannelPixelLayout>& aLayout,
                                   ErrorResult& aRv)
 {
   if (aImage.IsArrayBuffer() || aImage.IsArrayBufferView()) {
     return ImageBitmap::Create(this, aImage, aOffset, aLength, aFormat, aLayout,
                                aRv);
-  } else {
-    aRv.Throw(NS_ERROR_TYPE_ERR);
-    return nullptr;
-  }
+  }
+  aRv.Throw(NS_ERROR_TYPE_ERR);
+  return nullptr;
 }
 
 // Helper called by methods that move/resize the window,
 // to ensure the presContext (if any) is aware of resolution
 // change that may happen in multi-monitor configuration.
 void
 nsGlobalWindow::CheckForDPIChange()
 {

--- a/dom/base/nsImageLoadingContent.cpp
+++ b/dom/base/nsImageLoadingContent.cpp
@@ -1387,21 +1387,21 @@ nsImageLoadingContent::ClearPendingReque
   mPendingRequestFlags = 0;
 }
 
 bool*
 nsImageLoadingContent::GetRegisteredFlagForRequest(imgIRequest* aRequest)
 {
   if (aRequest == mCurrentRequest) {
     return &mCurrentRequestRegistered;
-  } else if (aRequest == mPendingRequest) {
+  }
+  if (aRequest == mPendingRequest) {
     return &mPendingRequestRegistered;
-  } else {
-    return nullptr;
   }
+  return nullptr;
 }
 
 void
 nsImageLoadingContent::ResetAnimationIfNeeded()
 {
   if (mCurrentRequest &&
       (mCurrentRequestFlags & REQUEST_NEEDS_ANIMATION_RESET)) {
     nsCOMPtr<imgIContainer> container;

--- a/dom/base/nsObjectLoadingContent.cpp
+++ b/dom/base/nsObjectLoadingContent.cpp
@@ -232,17 +232,18 @@ CheckPluginStopEvent::Run()
   LOG(("OBJLC [%p]: CheckPluginStopEvent - No frame, flushing layout", this));
   nsIDocument* composedDoc = content->GetComposedDoc();
   if (composedDoc) {
     composedDoc->FlushPendingNotifications(FlushType::Layout);
     if (objLC->mPendingCheckPluginStopEvent != this) {
       LOG(("OBJLC [%p]: CheckPluginStopEvent - superseded in layout flush",
            this));
       return NS_OK;
-    } else if (content->GetPrimaryFrame()) {
+    }
+    if (content->GetPrimaryFrame()) {
       LOG(("OBJLC [%p]: CheckPluginStopEvent - frame gained in layout flush",
            this));
       objLC->mPendingCheckPluginStopEvent = nullptr;
       return NS_OK;
     }
   }
 
   // Still no frame, suspend plugin. HasNewFrame will restart us when we
@@ -1028,20 +1029,19 @@ nsObjectLoadingContent::OnStartRequest(n
   if (mType == eType_Plugin) {
     if (!mInstanceOwner) {
       // We drop mChannel when stopping plugins, so something is wrong
       NS_NOTREACHED("Opened a channel in plugin mode, but don't have a plugin");
       return NS_BINDING_ABORTED;
     }
     if (MakePluginListener()) {
       return mFinalListener->OnStartRequest(aRequest, nullptr);
-    } else {
-      NS_NOTREACHED("Failed to create PluginStreamListener, aborting channel");
-      return NS_BINDING_ABORTED;
     }
+    NS_NOTREACHED("Failed to create PluginStreamListener, aborting channel");
+    return NS_BINDING_ABORTED;
   }
 
   // Otherwise we should be state loading, and call LoadObject with the channel
   if (mType != eType_Loading) {
     NS_NOTREACHED("Should be type loading at this point");
     return NS_BINDING_ABORTED;
   }
   NS_ASSERTION(!mChannelLoaded, "mChannelLoaded set already?");
@@ -1064,17 +1064,18 @@ nsObjectLoadingContent::OnStartRequest(n
       nsString message = NS_LITERAL_STRING("Blocking ") +
         NS_ConvertASCIItoUTF16(uri->GetSpecOrDefault().get()) +
         NS_LITERAL_STRING(" since it was found on an internal Firefox blocklist.");
       console->LogStringMessage(message.get());
     }
     Telemetry::Accumulate(Telemetry::PLUGIN_BLOCKED_FOR_STABILITY, 1);
     mContentBlockingEnabled = true;
     return NS_ERROR_FAILURE;
-  } else if (status == NS_ERROR_TRACKING_URI) {
+  }
+  if (status == NS_ERROR_TRACKING_URI) {
     mContentBlockingEnabled = true;
     return NS_ERROR_FAILURE;
   }
 
   if (!success) {
     LOG(("OBJLC [%p]: OnStartRequest: Request failed\n", this));
     // If the request fails, we still call LoadObject() to handle fallback
     // content and notifying of failure. (mChannelLoaded && !mChannel) indicates