LibJS: Move 'typeof' string functionality from AST to Value

We should be able to get the 'typeof' string for any value directly, so
this is now a standalone Value::typeof() method instead of being part of
UnaryExpression::execute().

Userland/Libraries/LibJS/AST.cpp

@@ -719,34 +719,7 @@ Value UnaryExpression::execute(Interpreter& interpreter, GlobalObject& global_ob
     case UnaryOp::Minus:
         return unary_minus(global_object, lhs_result);
     case UnaryOp::Typeof:
-        switch (lhs_result.type()) {
-        case Value::Type::Empty:
-            VERIFY_NOT_REACHED();
-            return {};
-        case Value::Type::Undefined:
-            return js_string(vm, "undefined");
-        case Value::Type::Null:
-            // yes, this is on purpose. yes, this is how javascript works.
-            // yes, it's silly.
-            return js_string(vm, "object");
-        case Value::Type::Int32:
-        case Value::Type::Double:
-            return js_string(vm, "number");
-        case Value::Type::String:
-            return js_string(vm, "string");
-        case Value::Type::Object:
-            if (lhs_result.is_function())
-                return js_string(vm, "function");
-            return js_string(vm, "object");
-        case Value::Type::Boolean:
-            return js_string(vm, "boolean");
-        case Value::Type::Symbol:
-            return js_string(vm, "symbol");
-        case Value::Type::BigInt:
-            return js_string(vm, "bigint");
-        default:
-            VERIFY_NOT_REACHED();
-        }
+        return js_string(vm, lhs_result.typeof());
     case UnaryOp::Void:
         return js_undefined();
     case UnaryOp::Delete:
@@ -1430,9 +1403,9 @@ Value AssignmentExpression::execute(Interpreter& interpreter, GlobalObject& glob
     }
 
     reference.put(global_object, rhs_result);
-
     if (interpreter.exception())
         return {};
+
     return rhs_result;
 }
 

Userland/Libraries/LibJS/Runtime/Value.cpp

@@ -264,6 +264,33 @@ bool Value::is_regexp(GlobalObject& global_object) const
     return is<RegExpObject>(as_object());
 }
 
+String Value::typeof() const
+{
+    switch (m_type) {
+    case Value::Type::Undefined:
+        return "undefined";
+    case Value::Type::Null:
+        return "object";
+    case Value::Type::Int32:
+    case Value::Type::Double:
+        return "number";
+    case Value::Type::String:
+        return "string";
+    case Value::Type::Object:
+        if (is_function())
+            return "function";
+        return "object";
+    case Value::Type::Boolean:
+        return "boolean";
+    case Value::Type::Symbol:
+        return "symbol";
+    case Value::Type::BigInt:
+        return "bigint";
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
 String Value::to_string_without_side_effects() const
 {
     switch (m_type) {
@@ -1364,5 +1391,4 @@ Object* species_constructor(GlobalObject& global_object, const Object& object, O
     vm.throw_exception<TypeError>(global_object, ErrorType::NotAConstructor, species.to_string_without_side_effects());
     return nullptr;
 }
-
 }

Userland/Libraries/LibJS/Runtime/Value.h

@@ -303,6 +303,8 @@ public:
         return *this;
     }
 
+    String typeof() const;
+
 private:
     Type m_type { Type::Empty };