diff --git a/dom/base/RemoteOuterWindowProxy.cpp b/dom/base/RemoteOuterWindowProxy.cpp
index 72562b72a93a..6c8738f2b39e 100644
--- a/dom/base/RemoteOuterWindowProxy.cpp
+++ b/dom/base/RemoteOuterWindowProxy.cpp
@@ -141,7 +141,7 @@ bool AppendIndexedPropertyNames(JSContext* aCx, BrowsingContext* aContext,
   }
 
   for (int32_t i = 0; i < length; ++i) {
-    aIndexedProps.infallibleAppend(INT_TO_JSID(i));
+    aIndexedProps.infallibleAppend(JS::PropertyKey::Int(i));
   }
   return true;
 }
diff --git a/dom/base/nsGlobalWindowOuter.cpp b/dom/base/nsGlobalWindowOuter.cpp
index 5e9f9d235c4b..416e34a05909 100644
--- a/dom/base/nsGlobalWindowOuter.cpp
+++ b/dom/base/nsGlobalWindowOuter.cpp
@@ -1081,7 +1081,7 @@ bool nsOuterWindowProxy::AppendIndexedPropertyNames(
     return false;
   }
   for (int32_t i = 0; i < int32_t(length); ++i) {
-    if (!props.append(INT_TO_JSID(i))) {
+    if (!props.append(JS::PropertyKey::Int(i))) {
       return false;
     }
   }
diff --git a/dom/bindings/Codegen.py b/dom/bindings/Codegen.py
index f24744d34144..cc3e31abe381 100644
--- a/dom/bindings/Codegen.py
+++ b/dom/bindings/Codegen.py
@@ -15064,7 +15064,7 @@ class CGDOMJSProxyHandler_ownPropNames(ClassMethod):
                 uint32_t length = UnwrapProxy(proxy)->Length(${callerType});
                 MOZ_ASSERT(int32_t(length) >= 0);
                 for (int32_t i = 0; i < int32_t(length); ++i) {
-                  if (!props.append(INT_TO_JSID(i))) {
+                  if (!props.append(JS::PropertyKey::Int(i))) {
                     return false;
                   }
                 }
diff --git a/js/public/Id.h b/js/public/Id.h
index d633edd8e74e..0fb7a454673a 100644
--- a/js/public/Id.h
+++ b/js/public/Id.h
@@ -118,6 +118,14 @@ struct PropertyKey {
 
   bool isWellKnownSymbol(JS::SymbolCode code) const;
 
+  static constexpr bool fitsInInt(int32_t i) { return i >= 0; }
+
+  static constexpr PropertyKey Int(int32_t i) {
+    MOZ_ASSERT(fitsInInt(i));
+    uint32_t bits = (static_cast<uint32_t>(i) << 1) | JSID_TYPE_INT_BIT;
+    return PropertyKey::fromRawBits(bits);
+  }
+
   // This API can be used by embedders to convert pinned (aka interned) strings,
   // as created by JS_AtomizeAndPinString, into PropertyKeys. This means the
   // string does not have to be explicitly rooted.
@@ -189,16 +197,6 @@ using jsid = JS::PropertyKey;
 #define JSID_INT_MIN 0
 #define JSID_INT_MAX INT32_MAX
 
-static MOZ_ALWAYS_INLINE bool INT_FITS_IN_JSID(int32_t i) { return i >= 0; }
-
-static MOZ_ALWAYS_INLINE jsid INT_TO_JSID(int32_t i) {
-  jsid id;
-  MOZ_ASSERT(INT_FITS_IN_JSID(i));
-  uint32_t bits = (static_cast<uint32_t>(i) << 1) | JSID_TYPE_INT_BIT;
-  JSID_BITS(id) = static_cast<size_t>(bits);
-  return id;
-}
-
 static MOZ_ALWAYS_INLINE jsid SYMBOL_TO_JSID(JS::Symbol* sym) {
   jsid id;
   MOZ_ASSERT(sym != nullptr);
diff --git a/js/src/builtin/Array.cpp b/js/src/builtin/Array.cpp
index 9034aa72fe1c..0b4adcf9f804 100644
--- a/js/src/builtin/Array.cpp
+++ b/js/src/builtin/Array.cpp
@@ -894,7 +894,7 @@ static inline bool ObjectMayHaveExtraIndexedOwnProperties(JSObject* obj) {
   }
 
   return ClassMayResolveId(*obj->runtimeFromAnyThread()->commonNames,
-                           obj->getClass(), INT_TO_JSID(0), obj);
+                           obj->getClass(), PropertyKey::Int(0), obj);
 }
 
 /*
@@ -1529,7 +1529,7 @@ static DenseElementResult ArrayReverseDenseKernel(JSContext* cx,
     }
 
     obj->setDenseElementHole(index);
-    return SuppressDeletedProperty(cx, obj, INT_TO_JSID(index));
+    return SuppressDeletedProperty(cx, obj, PropertyKey::Int(index));
   };
 
   RootedValue origlo(cx), orighi(cx);
diff --git a/js/src/builtin/JSON.cpp b/js/src/builtin/JSON.cpp
index 02aff9e66118..1499ad4d4d92 100644
--- a/js/src/builtin/JSON.cpp
+++ b/js/src/builtin/JSON.cpp
@@ -1199,7 +1199,7 @@ bool BuildImmutableProperty(JSContext* cx, HandleValue value, HandleId name,
       // Step 1.b.iv
       for (uint32_t i = 0; i < len; i++) {
         // Step 1.b.iv.1
-        childName.set(INT_TO_JSID(i));
+        childName.set(PropertyKey::Int(i));
 
         // Step 1.b.iv.2
         if (!GetProperty(cx, arr, value, childName, &childValue)) {
diff --git a/js/src/builtin/TestingFunctions.cpp b/js/src/builtin/TestingFunctions.cpp
index ab79d961158d..0d59a228e37e 100644
--- a/js/src/builtin/TestingFunctions.cpp
+++ b/js/src/builtin/TestingFunctions.cpp
@@ -4108,7 +4108,7 @@ static bool ReadGeckoProfilingStack(JSContext* cx, unsigned argc, Value* vp) {
         return false;
       }
 
-      idx = INT_TO_JSID(inlineFrameNo);
+      idx = PropertyKey::Int(inlineFrameNo);
       if (!JS_DefinePropertyById(cx, inlineStack, idx, inlineFrameInfo, 0)) {
         return false;
       }
@@ -4117,7 +4117,7 @@ static bool ReadGeckoProfilingStack(JSContext* cx, unsigned argc, Value* vp) {
     }
 
     // Push inline array into main array.
-    idx = INT_TO_JSID(physicalFrameNo);
+    idx = PropertyKey::Int(physicalFrameNo);
     if (!JS_DefinePropertyById(cx, stack, idx, inlineStack, 0)) {
       return false;
     }
@@ -4210,7 +4210,7 @@ JSObject* ShellAllocationMetadataBuilder::build(
   RootedValue callee(cx);
   for (NonBuiltinScriptFrameIter iter(cx); !iter.done(); ++iter) {
     if (iter.isFunctionFrame() && iter.compartment() == cx->compartment()) {
-      id = INT_TO_JSID(stackIndex);
+      id = PropertyKey::Int(stackIndex);
       RootedObject callee(cx, iter.callee(cx));
       if (!JS_DefinePropertyById(cx, stack, id, callee, JSPROP_ENUMERATE)) {
         oomUnsafe.crash("ShellAllocationMetadataBuilder::build");
diff --git a/js/src/debugger/Frame.cpp b/js/src/debugger/Frame.cpp
index 85ecea1fcf76..469ebd0c2058 100644
--- a/js/src/debugger/Frame.cpp
+++ b/js/src/debugger/Frame.cpp
@@ -1670,7 +1670,7 @@ DebuggerArguments* DebuggerArguments::create(JSContext* cx, HandleObject proto,
     if (!getobj) {
       return nullptr;
     }
-    id = INT_TO_JSID(i);
+    id = PropertyKey::Int(i);
     if (!NativeDefineAccessorProperty(cx, obj, id, getobj, nullptr,
                                       JSPROP_ENUMERATE)) {
       return nullptr;
diff --git a/js/src/debugger/Script.cpp b/js/src/debugger/Script.cpp
index 9c8764955c16..521baf7665aa 100644
--- a/js/src/debugger/Script.cpp
+++ b/js/src/debugger/Script.cpp
@@ -1664,7 +1664,7 @@ bool DebuggerScript::CallData::getAllOffsets() {
       RootedObject offsets(cx);
       RootedValue offsetsv(cx);
 
-      RootedId id(cx, INT_TO_JSID(lineno));
+      RootedId id(cx, PropertyKey::Int(lineno));
 
       bool found;
       if (!HasOwnProperty(cx, result, id, &found)) {
diff --git a/js/src/frontend/ObjLiteral.cpp b/js/src/frontend/ObjLiteral.cpp
index c90492288669..165b852dcfaa 100644
--- a/js/src/frontend/ObjLiteral.cpp
+++ b/js/src/frontend/ObjLiteral.cpp
@@ -134,7 +134,7 @@ bool InterpretObjLiteralObj(JSContext* cx, HandlePlainObject obj,
                   !insn.getKey().isArrayIndex());
 
     if (kind == PropertySetKind::Normal && insn.getKey().isArrayIndex()) {
-      propId = INT_TO_JSID(insn.getKey().getArrayIndex());
+      propId = PropertyKey::Int(insn.getKey().getArrayIndex());
     } else {
       JSAtom* jsatom =
           atomCache.getExistingAtomAt(cx, insn.getKey().getAtomIndex());
diff --git a/js/src/gdb/tests/test-jsid.cpp b/js/src/gdb/tests/test-jsid.cpp
index 0029b1a00d93..b0b8fc1b9852 100644
--- a/js/src/gdb/tests/test-jsid.cpp
+++ b/js/src/gdb/tests/test-jsid.cpp
@@ -8,7 +8,7 @@ FRAGMENT(jsid, simple) {
   JS::Rooted<JSString*> string(cx, JS_NewStringCopyZ(cx, chars));
   JS::Rooted<JSString*> interned(cx, JS_AtomizeAndPinString(cx, chars));
   JS::Rooted<jsid> string_id(cx, JS::PropertyKey::fromPinnedString(interned));
-  JS::Rooted<jsid> int_id(cx, INT_TO_JSID(1729));
+  JS::Rooted<jsid> int_id(cx, JS::PropertyKey::Int(1729));
   JS::Rooted<jsid> unique_symbol_id(
       cx, SYMBOL_TO_JSID(JS::NewSymbol(cx, interned)));
   JS::Rooted<jsid> registry_symbol_id(
diff --git a/js/src/jit/VMFunctions.cpp b/js/src/jit/VMFunctions.cpp
index 8c5864871729..448064bf61b1 100644
--- a/js/src/jit/VMFunctions.cpp
+++ b/js/src/jit/VMFunctions.cpp
@@ -1928,7 +1928,7 @@ bool HasNativeElementPure(JSContext* cx, NativeObject* obj, int32_t index,
     return true;
   }
 
-  jsid id = INT_TO_JSID(index);
+  jsid id = PropertyKey::Int(index);
   uint32_t unused;
   if (obj->shape()->lookup(cx, id, &unused)) {
     vp[0].setBoolean(true);
diff --git a/js/src/vm/ArgumentsObject.cpp b/js/src/vm/ArgumentsObject.cpp
index 4b8ff650854a..498a79e4455e 100644
--- a/js/src/vm/ArgumentsObject.cpp
+++ b/js/src/vm/ArgumentsObject.cpp
@@ -719,7 +719,7 @@ bool MappedArgumentsObject::obj_enumerate(JSContext* cx, HandleObject obj) {
   }
 
   for (unsigned i = 0; i < argsobj->initialLength(); i++) {
-    id = INT_TO_JSID(i);
+    id = PropertyKey::Int(i);
     if (!HasOwnProperty(cx, argsobj, id, &found)) {
       return false;
     }
@@ -1006,7 +1006,7 @@ bool UnmappedArgumentsObject::obj_enumerate(JSContext* cx, HandleObject obj) {
   }
 
   for (unsigned i = 0; i < argsobj->initialLength(); i++) {
-    id = INT_TO_JSID(i);
+    id = PropertyKey::Int(i);
     if (!HasOwnProperty(cx, argsobj, id, &found)) {
       return false;
     }
diff --git a/js/src/vm/Iteration.cpp b/js/src/vm/Iteration.cpp
index 1445dfff0135..24bcb9f34b6d 100644
--- a/js/src/vm/Iteration.cpp
+++ b/js/src/vm/Iteration.cpp
@@ -221,7 +221,7 @@ static bool EnumerateNativeProperties(JSContext* cx, HandleNativeObject pobj,
       } else {
         // Dense arrays never get so large that i would not fit into an
         // integer id.
-        if (!Enumerate<CheckForDuplicates>(cx, pobj, INT_TO_JSID(i),
+        if (!Enumerate<CheckForDuplicates>(cx, pobj, PropertyKey::Int(i),
                                            /* enumerable = */ true, flags,
                                            visited, props)) {
           return false;
@@ -244,7 +244,7 @@ static bool EnumerateNativeProperties(JSContext* cx, HandleNativeObject pobj,
       }
 
       for (size_t i = 0; i < len; i++) {
-        if (!Enumerate<CheckForDuplicates>(cx, pobj, INT_TO_JSID(i),
+        if (!Enumerate<CheckForDuplicates>(cx, pobj, PropertyKey::Int(i),
                                            /* enumerable = */ true, flags,
                                            visited, props)) {
           return false;
diff --git a/js/src/vm/JSAtom-inl.h b/js/src/vm/JSAtom-inl.h
index 322f616bd93a..956629eecd4c 100644
--- a/js/src/vm/JSAtom-inl.h
+++ b/js/src/vm/JSAtom-inl.h
@@ -25,7 +25,7 @@ MOZ_ALWAYS_INLINE jsid AtomToId(JSAtom* atom) {
 
   uint32_t index;
   if (atom->isIndex(&index) && index <= JSID_INT_MAX) {
-    return INT_TO_JSID(int32_t(index));
+    return JS::PropertyKey::Int(int32_t(index));
   }
 
   return JS::PropertyKey::fromNonIntAtom(atom);
@@ -42,11 +42,11 @@ MOZ_ALWAYS_INLINE bool ValueToIntId(const Value& v, jsid* id) {
     return false;
   }
 
-  if (!INT_FITS_IN_JSID(i)) {
+  if (!PropertyKey::fitsInInt(i)) {
     return false;
   }
 
-  *id = INT_TO_JSID(i);
+  *id = PropertyKey::Int(i);
   return true;
 }
 
@@ -135,7 +135,7 @@ bool IndexToIdSlow(JSContext* cx, uint32_t index, MutableHandleId idp);
 
 inline bool IndexToId(JSContext* cx, uint32_t index, MutableHandleId idp) {
   if (index <= JSID_INT_MAX) {
-    idp.set(INT_TO_JSID(index));
+    idp.set(PropertyKey::Int(index));
     return true;
   }
 
diff --git a/js/src/vm/NativeObject-inl.h b/js/src/vm/NativeObject-inl.h
index 8a92b9d01ac2..f274192f3bc1 100644
--- a/js/src/vm/NativeObject-inl.h
+++ b/js/src/vm/NativeObject-inl.h
@@ -60,7 +60,7 @@ inline void NativeObject::setDenseElementHole(uint32_t index) {
 }
 
 inline void NativeObject::removeDenseElementForSparseIndex(uint32_t index) {
-  MOZ_ASSERT(containsPure(INT_TO_JSID(index)));
+  MOZ_ASSERT(containsPure(PropertyKey::Int(index)));
   if (containsDenseElement(index)) {
     setDenseElementHole(index);
   }
diff --git a/js/src/vm/NativeObject.cpp b/js/src/vm/NativeObject.cpp
index f2885d075e1e..1b36af8afd27 100644
--- a/js/src/vm/NativeObject.cpp
+++ b/js/src/vm/NativeObject.cpp
@@ -1071,7 +1071,7 @@ static MOZ_ALWAYS_INLINE bool CallAddPropertyHookDense(JSContext* cx,
   if (MOZ_UNLIKELY(addProperty)) {
     MOZ_ASSERT(!cx->isHelperThreadContext());
 
-    RootedId id(cx, INT_TO_JSID(index));
+    RootedId id(cx, PropertyKey::Int(index));
     if (!CallJSAddPropertyOp(cx, addProperty, obj, id, value)) {
       obj->setDenseElementHole(index);
       return false;
@@ -1807,8 +1807,8 @@ static bool DefineNonexistentProperty(JSContext* cx, HandleNativeObject obj,
 bool js::AddOrUpdateSparseElementHelper(JSContext* cx, HandleArrayObject obj,
                                         int32_t int_id, HandleValue v,
                                         bool strict) {
-  MOZ_ASSERT(INT_FITS_IN_JSID(int_id));
-  RootedId id(cx, INT_TO_JSID(int_id));
+  MOZ_ASSERT(PropertyKey::fitsInInt(int_id));
+  RootedId id(cx, PropertyKey::Int(int_id));
 
   // This helper doesn't handle the case where the index may be in the dense
   // elements
@@ -2095,8 +2095,8 @@ bool js::GetSparseElementHelper(JSContext* cx, HandleArrayObject obj,
   MOZ_ASSERT_IF(obj->staticPrototype() != nullptr,
                 !ObjectMayHaveExtraIndexedProperties(obj->staticPrototype()));
 
-  MOZ_ASSERT(INT_FITS_IN_JSID(int_id));
-  RootedId id(cx, INT_TO_JSID(int_id));
+  MOZ_ASSERT(PropertyKey::fitsInInt(int_id));
+  RootedId id(cx, PropertyKey::Int(int_id));
 
   uint32_t index;
   PropMap* map = obj->shape()->lookup(cx, id, &index);
diff --git a/js/src/vm/ObjectOperations-inl.h b/js/src/vm/ObjectOperations-inl.h
index 35d8407c74f4..02b789924f62 100644
--- a/js/src/vm/ObjectOperations-inl.h
+++ b/js/src/vm/ObjectOperations-inl.h
@@ -207,7 +207,7 @@ inline bool GetElementNoGC(JSContext* cx, JSObject* obj,
     return false;
   }
 
-  return GetPropertyNoGC(cx, obj, receiver, INT_TO_JSID(index), vp);
+  return GetPropertyNoGC(cx, obj, receiver, PropertyKey::Int(index), vp);
 }
 
 static MOZ_ALWAYS_INLINE bool ClassMayResolveId(const JSAtomState& names,
diff --git a/js/src/vm/Runtime.h b/js/src/vm/Runtime.h
index bbc39efa3f5e..7e73165cefc0 100644
--- a/js/src/vm/Runtime.h
+++ b/js/src/vm/Runtime.h
@@ -1102,7 +1102,7 @@ static MOZ_ALWAYS_INLINE void MakeRangeGCSafe(Value* beg, Value* end) {
 }
 
 static MOZ_ALWAYS_INLINE void MakeRangeGCSafe(jsid* beg, jsid* end) {
-  std::fill(beg, end, INT_TO_JSID(0));
+  std::fill(beg, end, PropertyKey::Int(0));
 }
 
 static MOZ_ALWAYS_INLINE void MakeRangeGCSafe(jsid* vec, size_t len) {
diff --git a/js/src/vm/StructuredClone.cpp b/js/src/vm/StructuredClone.cpp
index 9d653d96dfd7..c4630de602b7 100644
--- a/js/src/vm/StructuredClone.cpp
+++ b/js/src/vm/StructuredClone.cpp
@@ -1469,7 +1469,7 @@ static bool TryAppendNativeProperties(JSContext* cx, HandleObject obj,
       continue;
     }
 
-    if (!entries.append(INT_TO_JSID(i - 1))) {
+    if (!entries.append(PropertyKey::Int(i - 1))) {
       return false;
     }
 
diff --git a/js/src/wasm/TypedObject.cpp b/js/src/wasm/TypedObject.cpp
index 06ae4d18c86b..019d58600e49 100644
--- a/js/src/wasm/TypedObject.cpp
+++ b/js/src/wasm/TypedObject.cpp
@@ -598,7 +598,7 @@ bool TypedObject::obj_newEnumerate(JSContext* cx, HandleObject obj,
   }
   RootedId id(cx);
   for (size_t index = 0; index < indexCount; index++) {
-    id = INT_TO_JSID(index);
+    id = PropertyKey::Int(index);
     properties.infallibleAppend(id);
   }
 
diff --git a/js/xpconnect/wrappers/XrayWrapper.cpp b/js/xpconnect/wrappers/XrayWrapper.cpp
index b99e50262df3..daa2081bb240 100644
--- a/js/xpconnect/wrappers/XrayWrapper.cpp
+++ b/js/xpconnect/wrappers/XrayWrapper.cpp
@@ -946,7 +946,7 @@ bool JSXrayTraits::enumerateNames(JSContext* cx, HandleObject wrapper,
         return false;
       }
       for (int32_t i = 0; i < int32_t(length); ++i) {
-        props.infallibleAppend(INT_TO_JSID(i));
+        props.infallibleAppend(PropertyKey::Int(i));
       }
     } else if (key == JSProto_Function) {
       if (!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_LENGTH))) {