diff --git a/dom/workers/RuntimeService.cpp b/dom/workers/RuntimeService.cpp
index 3fda0a78fd23..1dd4171b0a74 100644
--- a/dom/workers/RuntimeService.cpp
+++ b/dom/workers/RuntimeService.cpp
@@ -167,7 +167,7 @@ struct PrefTraits;
 
 template <>
 struct PrefTraits<bool> {
-  typedef bool PrefValueType;
+  using PrefValueType = bool;
 
   static const PrefValueType kDefaultValue = false;
 
@@ -184,7 +184,7 @@ struct PrefTraits<bool> {
 
 template <>
 struct PrefTraits<int32_t> {
-  typedef int32_t PrefValueType;
+  using PrefValueType = int32_t;
 
   static inline PrefValueType Get(const char* aPref) {
     AssertIsOnMainThread();
@@ -203,7 +203,7 @@ T GetWorkerPref(const nsACString& aPref,
                 bool* aPresent = nullptr) {
   AssertIsOnMainThread();
 
-  typedef PrefTraits<T> PrefHelper;
+  using PrefHelper = PrefTraits<T>;
 
   T result;
   bool present = true;
diff --git a/dom/workers/WorkerLoadInfo.cpp b/dom/workers/WorkerLoadInfo.cpp
index 7cc161a7acca..a0277e9ce16a 100644
--- a/dom/workers/WorkerLoadInfo.cpp
+++ b/dom/workers/WorkerLoadInfo.cpp
@@ -65,7 +65,7 @@ class MainThreadReleaseRunnable final : public Runnable {
 // Specialize this if there's some class that has multiple nsISupports bases.
 template <class T>
 struct ISupportsBaseInfo {
-  typedef T ISupportsBase;
+  using ISupportsBase = T;
 };
 
 template <template <class> class SmartPtr, class T>
diff --git a/dom/workers/WorkerNavigator.h b/dom/workers/WorkerNavigator.h
index df8206254948..364e5243a75d 100644
--- a/dom/workers/WorkerNavigator.h
+++ b/dom/workers/WorkerNavigator.h
@@ -35,8 +35,8 @@ class Connection;
 }  // namespace network
 
 class WorkerNavigator final : public nsWrapperCache {
-  typedef struct workerinternals::RuntimeService::NavigatorProperties
-      NavigatorProperties;
+  using NavigatorProperties =
+      workerinternals::RuntimeService::NavigatorProperties;
 
   NavigatorProperties mProperties;
   RefPtr<StorageManager> mStorageManager;
diff --git a/dom/workers/WorkerPrivate.cpp b/dom/workers/WorkerPrivate.cpp
index 496194cc67a5..ecec6c0af799 100644
--- a/dom/workers/WorkerPrivate.cpp
+++ b/dom/workers/WorkerPrivate.cpp
@@ -144,8 +144,8 @@ const uint32_t kClampTimeoutNestingLevel = 5u;
 
 template <class T>
 class UniquePtrComparator {
-  typedef UniquePtr<T> A;
-  typedef T* B;
+  using A = UniquePtr<T>;
+  using B = T*;
 
  public:
   bool Equals(const A& a, const A& b) const {
diff --git a/dom/workers/WorkerPrivate.h b/dom/workers/WorkerPrivate.h
index d4308262a4fb..15a82dacb097 100644
--- a/dom/workers/WorkerPrivate.h
+++ b/dom/workers/WorkerPrivate.h
@@ -78,7 +78,7 @@ class WorkerThread;
 // object. It exists to avoid changing a lot of code to use Mutex* instead of
 // Mutex&.
 class SharedMutex {
-  typedef mozilla::Mutex Mutex;
+  using Mutex = mozilla::Mutex;
 
   class RefCountedMutex final : public Mutex {
    public:
diff --git a/dom/workers/sharedworkers/SharedWorker.h b/dom/workers/sharedworkers/SharedWorker.h
index 165c40d4c01a..831802123665 100644
--- a/dom/workers/sharedworkers/SharedWorker.h
+++ b/dom/workers/sharedworkers/SharedWorker.h
@@ -32,8 +32,8 @@ class SharedWorkerChild;
  * we only allow top-level windows to create SharedWorkers.
  */
 class SharedWorker final : public DOMEventTargetHelper {
-  typedef mozilla::ErrorResult ErrorResult;
-  typedef mozilla::dom::GlobalObject GlobalObject;
+  using ErrorResult = mozilla::ErrorResult;
+  using GlobalObject = mozilla::dom::GlobalObject;
 
   RefPtr<nsPIDOMWindowInner> mWindow;
   RefPtr<SharedWorkerChild> mActor;