diff --git a/Libraries/LibJS/Runtime/BigIntObject.h b/Libraries/LibJS/Runtime/BigIntObject.h
index 0696c31cd85..49f5d6021a8 100644
--- a/Libraries/LibJS/Runtime/BigIntObject.h
+++ b/Libraries/LibJS/Runtime/BigIntObject.h
@@ -26,9 +26,14 @@ public:
 private:
     BigIntObject(BigInt&, Object& prototype);
 
+    virtual bool is_bigint_object() const final { return true; }
+
     virtual void visit_edges(Visitor&) override;
 
     GC::Ref<BigInt> m_bigint;
 };
 
+template<>
+inline bool Object::fast_is<BigIntObject>() const { return is_bigint_object(); }
+
 }
diff --git a/Libraries/LibJS/Runtime/BooleanObject.h b/Libraries/LibJS/Runtime/BooleanObject.h
index ae97c51b68c..21fb5f5e146 100644
--- a/Libraries/LibJS/Runtime/BooleanObject.h
+++ b/Libraries/LibJS/Runtime/BooleanObject.h
@@ -25,7 +25,12 @@ protected:
     BooleanObject(bool, Object& prototype);
 
 private:
+    virtual bool is_boolean_object() const final { return true; }
+
     bool m_value { false };
 };
 
+template<>
+inline bool Object::fast_is<BooleanObject>() const { return is_boolean_object(); }
+
 }
diff --git a/Libraries/LibJS/Runtime/Date.h b/Libraries/LibJS/Runtime/Date.h
index bcf0fc0f71f..f96ae10e658 100644
--- a/Libraries/LibJS/Runtime/Date.h
+++ b/Libraries/LibJS/Runtime/Date.h
@@ -31,9 +31,14 @@ public:
 private:
     Date(double date_value, Object& prototype);
 
+    virtual bool is_date() const final { return true; }
+
     double m_date_value { 0 }; // [[DateValue]]
 };
 
+template<>
+inline bool Object::fast_is<Date>() const { return is_date(); }
+
 // 21.4.1.22 Time Zone Identifier Record, https://tc39.es/ecma262/#sec-time-zone-identifier-record
 struct TimeZoneIdentifier {
     String identifier;         // [[Identifier]]
diff --git a/Libraries/LibJS/Runtime/Error.h b/Libraries/LibJS/Runtime/Error.h
index b63befc3570..3632a83c936 100644
--- a/Libraries/LibJS/Runtime/Error.h
+++ b/Libraries/LibJS/Runtime/Error.h
@@ -47,10 +47,15 @@ protected:
     explicit Error(Object& prototype);
 
 private:
+    virtual bool is_error() const final { return true; }
+
     void populate_stack();
     Vector<TracebackFrame, 32> m_traceback;
 };
 
+template<>
+inline bool Object::fast_is<Error>() const { return is_error(); }
+
 // NOTE: Making these inherit from Error is not required by the spec but
 //       our way of implementing the [[ErrorData]] internal slot, which is
 //       used in Object.prototype.toString().
diff --git a/Libraries/LibJS/Runtime/NumberObject.h b/Libraries/LibJS/Runtime/NumberObject.h
index 13fb041c2d0..dd4444d4742 100644
--- a/Libraries/LibJS/Runtime/NumberObject.h
+++ b/Libraries/LibJS/Runtime/NumberObject.h
@@ -25,7 +25,12 @@ protected:
     NumberObject(double, Object& prototype);
 
 private:
+    virtual bool is_number_object() const final { return true; }
+
     double m_value { 0 };
 };
 
+template<>
+inline bool Object::fast_is<NumberObject>() const { return is_number_object(); }
+
 }
diff --git a/Libraries/LibJS/Runtime/Object.h b/Libraries/LibJS/Runtime/Object.h
index 5e1687c8a99..6fdce3c335b 100644
--- a/Libraries/LibJS/Runtime/Object.h
+++ b/Libraries/LibJS/Runtime/Object.h
@@ -190,6 +190,12 @@ public:
 
     virtual bool is_dom_node() const { return false; }
     virtual bool is_function() const { return false; }
+    virtual bool is_error() const { return false; }
+    virtual bool is_date() const { return false; }
+    virtual bool is_number_object() const { return false; }
+    virtual bool is_boolean_object() const { return false; }
+    virtual bool is_regexp_object() const { return false; }
+    virtual bool is_bigint_object() const { return false; }
     virtual bool is_string_object() const { return false; }
     virtual bool is_global_object() const { return false; }
     virtual bool is_proxy_object() const { return false; }
diff --git a/Libraries/LibJS/Runtime/RegExpObject.h b/Libraries/LibJS/Runtime/RegExpObject.h
index 32c1926dffa..b7ebe63facc 100644
--- a/Libraries/LibJS/Runtime/RegExpObject.h
+++ b/Libraries/LibJS/Runtime/RegExpObject.h
@@ -74,6 +74,7 @@ private:
     RegExpObject(Object& prototype);
     RegExpObject(Regex<ECMA262> regex, String pattern, String flags, Object& prototype);
 
+    virtual bool is_regexp_object() const final { return true; }
     virtual void visit_edges(Visitor&) override;
 
     String m_pattern;
@@ -85,6 +86,9 @@ private:
     Optional<Regex<ECMA262>> m_regex;
 };
 
+template<>
+inline bool Object::fast_is<RegExpObject>() const { return is_regexp_object(); }
+
 AK_ENUM_BITWISE_OPERATORS(RegExpObject::Flags);
 
 }