diff --git a/js/public/experimental/TypedData.h b/js/public/experimental/TypedData.h
index 963e9f433dcd..cdc57c40be01 100644
--- a/js/public/experimental/TypedData.h
+++ b/js/public/experimental/TypedData.h
@@ -309,7 +309,7 @@ extern JS_FRIEND_API uint32_t JS_GetTypedArrayLength(JSObject* obj);
  * be known that it would pass such a test: it is a typed array or a wrapper of
  * a typed array, and the unwrapping will succeed.
  */
-extern JS_FRIEND_API uint32_t JS_GetTypedArrayByteOffset(JSObject* obj);
+extern JS_FRIEND_API size_t JS_GetTypedArrayByteOffset(JSObject* obj);
 
 /**
  * Return the byte length of a typed array.
@@ -318,17 +318,17 @@ extern JS_FRIEND_API uint32_t JS_GetTypedArrayByteOffset(JSObject* obj);
  * be known that it would pass such a test: it is a typed array or a wrapper of
  * a typed array, and the unwrapping will succeed.
  */
-extern JS_FRIEND_API uint32_t JS_GetTypedArrayByteLength(JSObject* obj);
+extern JS_FRIEND_API size_t JS_GetTypedArrayByteLength(JSObject* obj);
 
 /**
  * More generic name for JS_GetTypedArrayByteLength to cover DataViews as well
  */
-extern JS_FRIEND_API uint32_t JS_GetArrayBufferViewByteLength(JSObject* obj);
+extern JS_FRIEND_API size_t JS_GetArrayBufferViewByteLength(JSObject* obj);
 
 /**
  * More generic name for JS_GetTypedArrayByteOffset to cover DataViews as well
  */
-extern JS_FRIEND_API uint32_t JS_GetArrayBufferViewByteOffset(JSObject* obj);
+extern JS_FRIEND_API size_t JS_GetArrayBufferViewByteOffset(JSObject* obj);
 
 /*
  * Return a pointer to the start of the data referenced by a typed array. The
diff --git a/js/src/ctypes/CTypes.cpp b/js/src/ctypes/CTypes.cpp
index d0822b03d06a..84c5128f576a 100644
--- a/js/src/ctypes/CTypes.cpp
+++ b/js/src/ctypes/CTypes.cpp
@@ -1259,8 +1259,8 @@ static bool ArgumentLengthError(JSContext* cx, const char* fun,
   return false;
 }
 
-static bool ArrayLengthMismatch(JSContext* cx, unsigned expectedLength,
-                                HandleObject arrObj, unsigned actualLength,
+static bool ArrayLengthMismatch(JSContext* cx, size_t expectedLength,
+                                HandleObject arrObj, size_t actualLength,
                                 HandleValue actual, ConversionType convType) {
   MOZ_ASSERT(arrObj && CType::IsCType(arrObj));
 
@@ -3673,13 +3673,13 @@ static bool ImplicitConvert(JSContext* cx, HandleValue val,
                              arrObj, arrIndex);
           }
 
-          uint32_t sourceLength = JS_GetTypedArrayByteLength(valObj);
+          size_t sourceLength = JS_GetTypedArrayByteLength(valObj);
           size_t elementSize = CType::GetSize(baseType);
           size_t arraySize = elementSize * targetLength;
-          if (arraySize != size_t(sourceLength)) {
+          if (arraySize != sourceLength) {
             MOZ_ASSERT(!funObj);
-            return ArrayLengthMismatch(cx, arraySize, targetType,
-                                       size_t(sourceLength), val, convType);
+            return ArrayLengthMismatch(cx, arraySize, targetType, sourceLength,
+                                       val, convType);
           }
           SharedMem<void*> target = SharedMem<void*>::unshared(buffer);
           JS::AutoCheckCannotGC nogc;
diff --git a/js/src/jsapi-tests/testLargeArrayBuffers.cpp b/js/src/jsapi-tests/testLargeArrayBuffers.cpp
index d464a057faef..894a27820d28 100644
--- a/js/src/jsapi-tests/testLargeArrayBuffers.cpp
+++ b/js/src/jsapi-tests/testLargeArrayBuffers.cpp
@@ -40,6 +40,10 @@ BEGIN_TEST(testLargeArrayBuffers) {
   {
     RootedObject tarr(cx, JS_NewUint8Array(cx, nbytes));
     CHECK(JS_IsTypedArrayObject(tarr));
+    CHECK_EQUAL(JS_GetArrayBufferViewByteOffset(tarr), 0u);
+    CHECK_EQUAL(JS_GetArrayBufferViewByteLength(tarr), nbytes);
+    CHECK_EQUAL(JS_GetTypedArrayByteOffset(tarr), 0u);
+    CHECK_EQUAL(JS_GetTypedArrayByteLength(tarr), nbytes);
 
     length = 0;
     js::GetArrayBufferViewLengthAndData(tarr, &length, &isShared, &data);
@@ -55,6 +59,10 @@ BEGIN_TEST(testLargeArrayBuffers) {
     RootedObject tarr(cx,
                       JS_NewInt16ArrayWithBuffer(cx, buffer, 0, nbytes / 2));
     CHECK(JS_IsTypedArrayObject(tarr));
+    CHECK_EQUAL(JS_GetArrayBufferViewByteOffset(tarr), 0u);
+    CHECK_EQUAL(JS_GetArrayBufferViewByteLength(tarr), nbytes);
+    CHECK_EQUAL(JS_GetTypedArrayByteOffset(tarr), 0u);
+    CHECK_EQUAL(JS_GetTypedArrayByteLength(tarr), nbytes);
 
     length = 0;
     js::GetArrayBufferViewLengthAndData(tarr, &length, &isShared, &data);
@@ -70,11 +78,32 @@ BEGIN_TEST(testLargeArrayBuffers) {
   {
     RootedObject dv(cx, JS_NewDataView(cx, buffer, 0, nbytes - 10));
     CHECK(JS_IsArrayBufferViewObject(dv));
+    CHECK_EQUAL(JS_GetArrayBufferViewByteOffset(dv), 0u);
+    CHECK_EQUAL(JS_GetArrayBufferViewByteLength(dv), nbytes - 10);
 
     length = 0;
     js::GetArrayBufferViewLengthAndData(dv, &length, &isShared, &data);
     CHECK_EQUAL(length, nbytes - 10);
   }
+
+  // Int8Array with large byteOffset.
+  {
+    RootedObject tarr(cx,
+                      JS_NewInt8ArrayWithBuffer(cx, buffer, nbytes - 200, 32));
+    CHECK(JS_IsTypedArrayObject(tarr));
+    CHECK_EQUAL(JS_GetArrayBufferViewByteOffset(tarr), nbytes - 200);
+    CHECK_EQUAL(JS_GetArrayBufferViewByteLength(tarr), 32u);
+    CHECK_EQUAL(JS_GetTypedArrayByteOffset(tarr), nbytes - 200);
+    CHECK_EQUAL(JS_GetTypedArrayByteLength(tarr), 32u);
+  }
+
+  // DataView with large byteOffset.
+  {
+    RootedObject dv(cx, JS_NewDataView(cx, buffer, nbytes - 200, 32));
+    CHECK(JS_IsArrayBufferViewObject(dv));
+    CHECK_EQUAL(JS_GetArrayBufferViewByteOffset(dv), nbytes - 200);
+    CHECK_EQUAL(JS_GetArrayBufferViewByteLength(dv), 32u);
+  }
 #endif
 
   return true;
diff --git a/js/src/vm/ArrayBufferViewObject.cpp b/js/src/vm/ArrayBufferViewObject.cpp
index 00dbab4ed965..2ecf0863955a 100644
--- a/js/src/vm/ArrayBufferViewObject.cpp
+++ b/js/src/vm/ArrayBufferViewObject.cpp
@@ -237,7 +237,7 @@ JS_FRIEND_API JSObject* JS_GetArrayBufferViewBuffer(JSContext* cx,
   return buffer;
 }
 
-JS_FRIEND_API uint32_t JS_GetArrayBufferViewByteLength(JSObject* obj) {
+JS_FRIEND_API size_t JS_GetArrayBufferViewByteLength(JSObject* obj) {
   obj = obj->maybeUnwrapAs<ArrayBufferViewObject>();
   if (!obj) {
     return 0;
@@ -245,10 +245,10 @@ JS_FRIEND_API uint32_t JS_GetArrayBufferViewByteLength(JSObject* obj) {
   BufferSize length = obj->is<DataViewObject>()
                           ? obj->as<DataViewObject>().byteLength()
                           : obj->as<TypedArrayObject>().byteLength();
-  return length.deprecatedGetUint32();
+  return length.get();
 }
 
-JS_FRIEND_API uint32_t JS_GetArrayBufferViewByteOffset(JSObject* obj) {
+JS_FRIEND_API size_t JS_GetArrayBufferViewByteOffset(JSObject* obj) {
   obj = obj->maybeUnwrapAs<ArrayBufferViewObject>();
   if (!obj) {
     return 0;
@@ -256,7 +256,7 @@ JS_FRIEND_API uint32_t JS_GetArrayBufferViewByteOffset(JSObject* obj) {
   BufferSize offset = obj->is<DataViewObject>()
                           ? obj->as<DataViewObject>().byteOffset()
                           : obj->as<TypedArrayObject>().byteOffset();
-  return offset.deprecatedGetUint32();
+  return offset.get();
 }
 
 JS_FRIEND_API JSObject* JS_GetObjectAsArrayBufferView(JSObject* obj,
diff --git a/js/src/vm/TypedArrayObject.cpp b/js/src/vm/TypedArrayObject.cpp
index 7ceb5f0f29e4..98db334ac762 100644
--- a/js/src/vm/TypedArrayObject.cpp
+++ b/js/src/vm/TypedArrayObject.cpp
@@ -2714,20 +2714,20 @@ JS_FRIEND_API uint32_t JS_GetTypedArrayLength(JSObject* obj) {
   return tarr->length().deprecatedGetUint32();
 }
 
-JS_FRIEND_API uint32_t JS_GetTypedArrayByteOffset(JSObject* obj) {
+JS_FRIEND_API size_t JS_GetTypedArrayByteOffset(JSObject* obj) {
   TypedArrayObject* tarr = obj->maybeUnwrapAs<TypedArrayObject>();
   if (!tarr) {
     return 0;
   }
-  return tarr->byteOffset().deprecatedGetUint32();
+  return tarr->byteOffset().get();
 }
 
-JS_FRIEND_API uint32_t JS_GetTypedArrayByteLength(JSObject* obj) {
+JS_FRIEND_API size_t JS_GetTypedArrayByteLength(JSObject* obj) {
   TypedArrayObject* tarr = obj->maybeUnwrapAs<TypedArrayObject>();
   if (!tarr) {
     return 0;
   }
-  return tarr->byteLength().deprecatedGetUint32();
+  return tarr->byteLength().get();
 }
 
 JS_FRIEND_API bool JS_GetTypedArraySharedness(JSObject* obj) {