diff --git a/rhino/src/main/java/org/mozilla/javascript/AbstractEcmaObjectOperations.java b/rhino/src/main/java/org/mozilla/javascript/AbstractEcmaObjectOperations.java
index b35b4879ce..60976f69ad 100644
--- a/rhino/src/main/java/org/mozilla/javascript/AbstractEcmaObjectOperations.java
+++ b/rhino/src/main/java/org/mozilla/javascript/AbstractEcmaObjectOperations.java
@@ -7,6 +7,7 @@
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Predicate;
+import org.mozilla.javascript.ScriptableObject.DescriptorInfo;
 
 /**
  * Abstract Object Operations as defined by EcmaScript
@@ -83,12 +84,11 @@ static boolean testIntegrityLevel(Context cx, Object o, INTEGRITY_LEVEL level) {
             ids = obj.getIds(map, true, true);
         }
         for (Object name : ids) {
-            ScriptableObject desc = obj.getOwnPropertyDescriptor(cx, name);
-            if (Boolean.TRUE.equals(desc.get("configurable"))) return false;
+            DescriptorInfo desc = obj.getOwnPropertyDescriptor(cx, name);
+            if (desc.isConfigurable()) return false;
 
-            if (level == INTEGRITY_LEVEL.FROZEN
-                    && ScriptableObject.isDataDescriptor(desc)
-                    && Boolean.TRUE.equals(desc.get("writable"))) return false;
+            if (level == INTEGRITY_LEVEL.FROZEN && desc.isDataDescriptor() && desc.isWritable())
+                return false;
         }
 
         return true;
@@ -150,21 +150,20 @@ static boolean setIntegrityLevel(Context cx, Object o, INTEGRITY_LEVEL level) {
             ids = obj.getIds(map, true, true);
         }
         for (Object key : ids) {
-            ScriptableObject desc = obj.getOwnPropertyDescriptor(cx, key);
+            DescriptorInfo desc = obj.getOwnPropertyDescriptor(cx, key);
 
             if (level == INTEGRITY_LEVEL.SEALED) {
-                if (Boolean.TRUE.equals(desc.get("configurable"))) {
-                    desc.put("configurable", desc, Boolean.FALSE);
+                if (desc.isConfigurable()) {
+                    desc.configurable = false;
 
                     obj.defineOwnProperty(cx, key, desc, false);
                 }
             } else {
-                if (ScriptableObject.isDataDescriptor(desc)
-                        && Boolean.TRUE.equals(desc.get("writable"))) {
-                    desc.put("writable", desc, Boolean.FALSE);
+                if (desc.isDataDescriptor() && desc.isWritable()) {
+                    desc.writable = false;
                 }
-                if (Boolean.TRUE.equals(desc.get("configurable"))) {
-                    desc.put("configurable", desc, Boolean.FALSE);
+                if (desc.isConfigurable()) {
+                    desc.configurable = false;
                 }
                 obj.defineOwnProperty(cx, key, desc, false);
             }
@@ -402,7 +401,7 @@ public static long lengthOfArrayLike(Context cx, Scriptable o) {
      * IsCompatiblePropertyDescriptor (Extensible, Desc, Current)</a>
      */
     static boolean isCompatiblePropertyDescriptor(
-            Context cx, boolean extensible, ScriptableObject desc, ScriptableObject current) {
+            Context cx, boolean extensible, DescriptorInfo desc, DescriptorInfo current) {
         return validateAndApplyPropertyDescriptor(
                 cx,
                 Undefined.SCRIPTABLE_UNDEFINED,
@@ -424,15 +423,14 @@ static boolean validateAndApplyPropertyDescriptor(
             Scriptable o,
             Scriptable p,
             boolean extensible,
-            ScriptableObject desc,
-            ScriptableObject current) {
+            DescriptorInfo desc,
+            DescriptorInfo current) {
         if (Undefined.isUndefined(current)) {
             if (!extensible) {
                 return false;
             }
 
-            if (ScriptableObject.isGenericDescriptor(desc)
-                    || ScriptableObject.isDataDescriptor(desc)) {
+            if (desc.isGenericDescriptor() || desc.isDataDescriptor()) {
                 /*
                 i. i. If O is not undefined, create an own data property named P of object O whose [[Value]], [[Writable]], [[Enumerable]], and [[Configurable]] attribute values are described by Desc.
                   If the value of an attribute field of Desc is absent, the attribute of the newly created property is set to its default value.
@@ -445,32 +443,35 @@ static boolean validateAndApplyPropertyDescriptor(
             return true;
         }
 
-        if (desc.getIds().length == 0) {
+        if (!desc.hasEnumerable()
+                && !desc.hasConfigurable()
+                && !desc.hasWritable()
+                && !desc.hasGetter()
+                && !desc.hasSetter()
+                && !desc.hasValue()) {
             return true;
         }
 
-        if (Boolean.FALSE.equals(current.get("configurable"))) {
-            if (Boolean.TRUE.equals(ScriptableObject.hasProperty(desc, "configurable"))
-                    && Boolean.TRUE.equals(desc.get("configurable"))) {
+        if (current.isConfigurable(false)) {
+            if (desc.isConfigurable()) {
                 return false;
             }
 
-            if (Boolean.TRUE.equals(ScriptableObject.hasProperty(desc, "enumerable"))
-                    && !Objects.equals(desc.get("enumerable"), current.get("enumerable"))) {
+            if (desc.hasEnumerable() && !Objects.equals(desc.enumerable, current.enumerable)) {
                 return false;
             }
         }
 
-        if (ScriptableObject.isGenericDescriptor(desc)) {
+        if (desc.isGenericDescriptor()) {
             return true;
         }
 
-        if (ScriptableObject.isDataDescriptor(current) != ScriptableObject.isDataDescriptor(desc)) {
-            if (Boolean.FALSE.equals(current.get("configurable"))) {
+        if (current.isDataDescriptor() != desc.isDataDescriptor()) {
+            if (current.isConfigurable(false)) {
                 return false;
             }
-            if (ScriptableObject.isDataDescriptor(current)) {
-                if (Boolean.FALSE.equals(current.get("configurable"))) {
+            if (current.isDataDescriptor()) {
+                if (current.isConfigurable(false)) {
                     // i. i. If O is not undefined, convert the property named P of object O from a
                     // data property to an accessor property. Preserve the existing values of the
                     // converted property's [[Configurable]] and [[Enumerable]] attributes and set
@@ -482,28 +483,22 @@ static boolean validateAndApplyPropertyDescriptor(
                     // the rest of the property's attributes to their default values.
                 }
             }
-        } else if (ScriptableObject.isDataDescriptor(current)
-                && ScriptableObject.isDataDescriptor(desc)) {
-            if (Boolean.FALSE.equals(current.get("configurable"))
-                    && Boolean.FALSE.equals(current.get("writable"))) {
-                if (Boolean.TRUE.equals(ScriptableObject.hasProperty(desc, "writable"))
-                        && Boolean.TRUE.equals(desc.get("writable"))) {
+        } else if (current.isDataDescriptor() && desc.isDataDescriptor()) {
+            if (current.isConfigurable(false) && current.isWritable(false)) {
+                if (desc.isWritable()) {
                     return false;
                 }
-                if (Boolean.TRUE.equals(ScriptableObject.hasProperty(desc, "value"))
-                        && !Objects.equals(desc.get("value"), current.get("value"))) {
+                if (desc.hasValue() && !Objects.equals(desc.value, current.value)) {
                     return false;
                 }
                 return true;
             }
         } else {
-            if (Boolean.FALSE.equals(current.get("configurable"))) {
-                if (Boolean.TRUE.equals(ScriptableObject.hasProperty(desc, "set"))
-                        && !Objects.equals(desc.get("set"), current.get("set"))) {
+            if (current.isConfigurable(false)) {
+                if (desc.hasSetter() && !Objects.equals(desc.setter, current.setter)) {
                     return false;
                 }
-                if (Boolean.TRUE.equals(ScriptableObject.hasProperty(desc, "get"))
-                        && !Objects.equals(desc.get("get"), current.get("get"))) {
+                if (desc.hasGetter() && !Objects.equals(desc.getter, current.getter)) {
                     return false;
                 }
                 return true;
diff --git a/rhino/src/main/java/org/mozilla/javascript/AccessorSlot.java b/rhino/src/main/java/org/mozilla/javascript/AccessorSlot.java
index 768544d07a..f0e941dae0 100644
--- a/rhino/src/main/java/org/mozilla/javascript/AccessorSlot.java
+++ b/rhino/src/main/java/org/mozilla/javascript/AccessorSlot.java
@@ -1,5 +1,7 @@
 package org.mozilla.javascript;
 
+import org.mozilla.javascript.ScriptableObject.DescriptorInfo;
+
 /**
  * This is a specialization of Slot to store various types of values that are retrieved dynamically
  * using Java and JavaScript functions. Unlike LambdaSlot, the fact that these values are accessed
@@ -43,45 +45,40 @@ boolean isSetterSlot() {
     }
 
     @Override
-    ScriptableObject getPropertyDescriptor(Context cx, Scriptable scope) {
+    DescriptorInfo getPropertyDescriptor(Context cx, Scriptable scope) {
         // It sounds logical that this would be the same as the logic for a normal Slot,
         // but the spec is super pedantic about things like the order of properties here,
         // so we need special support here.
 
-        ScriptableObject desc = (ScriptableObject) cx.newObject(scope);
         int attr = getAttributes();
-
+        DescriptorInfo desc;
         boolean es6 = cx.getLanguageVersion() >= Context.VERSION_ES6;
         if (es6) {
+            desc = new DescriptorInfo(ScriptableObject.NOT_FOUND, attr, false);
             if (getter == null && setter == null) {
-                desc.defineProperty(
-                        "writable",
-                        (attr & ScriptableObject.READONLY) == 0,
-                        ScriptableObject.EMPTY);
+                desc.writable = (attr & ScriptableObject.READONLY) == 0;
             }
         } else {
-            desc.setCommonDescriptorProperties(attr, getter == null && setter == null);
+            desc =
+                    new DescriptorInfo(
+                            ScriptableObject.NOT_FOUND, attr, getter == null && setter == null);
         }
 
         String fName = name == null ? "f" : name.toString();
         if (getter != null) {
             Function f = getter.asGetterFunction(fName, scope);
-            desc.defineProperty("get", f == null ? Undefined.instance : f, ScriptableObject.EMPTY);
+            desc.getter = f == null ? Undefined.instance : f;
         }
         if (setter != null) {
             Function f = setter.asSetterFunction(fName, scope);
-            desc.defineProperty("set", f == null ? Undefined.instance : f, ScriptableObject.EMPTY);
+            desc.setter = f == null ? Undefined.instance : f;
         } else if (es6) {
-            desc.defineProperty("set", Undefined.instance, ScriptableObject.EMPTY);
+            desc.setter = Undefined.instance;
         }
 
         if (es6) {
-            desc.defineProperty(
-                    "enumerable", (attr & ScriptableObject.DONTENUM) == 0, ScriptableObject.EMPTY);
-            desc.defineProperty(
-                    "configurable",
-                    (attr & ScriptableObject.PERMANENT) == 0,
-                    ScriptableObject.EMPTY);
+            desc.enumerable = (attr & ScriptableObject.DONTENUM) == 0;
+            desc.configurable = (attr & ScriptableObject.PERMANENT) == 0;
         }
 
         return desc;
diff --git a/rhino/src/main/java/org/mozilla/javascript/Arguments.java b/rhino/src/main/java/org/mozilla/javascript/Arguments.java
index aa8f3730d0..84a23ca5ac 100644
--- a/rhino/src/main/java/org/mozilla/javascript/Arguments.java
+++ b/rhino/src/main/java/org/mozilla/javascript/Arguments.java
@@ -254,7 +254,7 @@ Object[] getIds(CompoundOperationMap map, boolean getNonEnumerable, boolean getS
     }
 
     @Override
-    protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
+    protected DescriptorInfo getOwnPropertyDescriptor(Context cx, Object id) {
         if (ScriptRuntime.isSymbol(id) || id instanceof Scriptable) {
             return super.getOwnPropertyDescriptor(cx, id);
         }
@@ -272,18 +272,16 @@ protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
             value = getFromActivation(index);
         }
         if (super.has(index, this)) { // the descriptor has been redefined
-            ScriptableObject desc = super.getOwnPropertyDescriptor(cx, id);
-            desc.put("value", desc, value);
+            DescriptorInfo desc = super.getOwnPropertyDescriptor(cx, id);
+            desc.value = value;
             return desc;
         }
-        Scriptable scope = getParentScope();
-        if (scope == null) scope = this;
-        return buildDataDescriptor(scope, value, EMPTY);
+        return buildDataDescriptor(value, EMPTY);
     }
 
     @Override
     protected boolean defineOwnProperty(
-            Context cx, Object id, ScriptableObject desc, boolean checkValid) {
+            Context cx, Object id, DescriptorInfo desc, boolean checkValid) {
         super.defineOwnProperty(cx, id, desc, checkValid);
         if (ScriptRuntime.isSymbol(id)) {
             return true;
@@ -296,17 +294,17 @@ protected boolean defineOwnProperty(
         Object value = arg(index);
         if (value == NOT_FOUND) return true;
 
-        if (isAccessorDescriptor(desc)) {
+        if (desc.isAccessorDescriptor()) {
             removeArg(index);
             return true;
         }
 
-        Object newValue = getProperty(desc, "value");
+        Object newValue = desc.value;
         if (newValue == NOT_FOUND) return true;
 
         replaceArg(index, newValue);
 
-        if (isFalse(getProperty(desc, "writable"))) {
+        if (isFalse(desc.writable)) {
             removeArg(index);
         }
         return true;
diff --git a/rhino/src/main/java/org/mozilla/javascript/ArrayLikeAbstractOperations.java b/rhino/src/main/java/org/mozilla/javascript/ArrayLikeAbstractOperations.java
index 86d5f6753f..299264fb1f 100644
--- a/rhino/src/main/java/org/mozilla/javascript/ArrayLikeAbstractOperations.java
+++ b/rhino/src/main/java/org/mozilla/javascript/ArrayLikeAbstractOperations.java
@@ -6,6 +6,7 @@
 
 import java.io.Serializable;
 import java.util.Comparator;
+import org.mozilla.javascript.ScriptableObject.DescriptorInfo;
 
 /** Contains implementation of shared methods useful for arrays and typed arrays. */
 public class ArrayLikeAbstractOperations {
@@ -275,11 +276,7 @@ static void defineElem(Context cx, Scriptable target, long index, Object value)
         if (!(target instanceof NativeArray && ((NativeArray) target).getDenseOnly())
                 && target instanceof ScriptableObject) {
             var so = (ScriptableObject) target;
-            ScriptableObject desc = new NativeObject();
-            desc.defineProperty("value", value, 0);
-            desc.defineProperty("writable", Boolean.TRUE, 0);
-            desc.defineProperty("enumerable", Boolean.TRUE, 0);
-            desc.defineProperty("configurable", Boolean.TRUE, 0);
+            var desc = new DescriptorInfo(true, true, true, value);
             so.defineOwnProperty(cx, index, desc);
             return;
         }
diff --git a/rhino/src/main/java/org/mozilla/javascript/BoundFunction.java b/rhino/src/main/java/org/mozilla/javascript/BoundFunction.java
index b756e29375..16d3f9b216 100644
--- a/rhino/src/main/java/org/mozilla/javascript/BoundFunction.java
+++ b/rhino/src/main/java/org/mozilla/javascript/BoundFunction.java
@@ -38,13 +38,7 @@ public BoundFunction(
         ScriptRuntime.setFunctionProtoAndParent(this, cx, scope, false);
 
         Function thrower = ScriptRuntime.typeErrorThrower(cx);
-        NativeObject throwing = new NativeObject();
-        ScriptRuntime.setBuiltinProtoAndParent(throwing, scope, TopLevel.Builtins.Object);
-        throwing.put("get", throwing, thrower);
-        throwing.put("set", throwing, thrower);
-        throwing.put("enumerable", throwing, Boolean.FALSE);
-        throwing.put("configurable", throwing, Boolean.FALSE);
-        throwing.preventExtensions();
+        var throwing = new DescriptorInfo(false, NOT_FOUND, false, thrower, thrower, NOT_FOUND);
 
         this.defineOwnProperty(cx, "caller", throwing, false);
         this.defineOwnProperty(cx, "arguments", throwing, false);
diff --git a/rhino/src/main/java/org/mozilla/javascript/BuiltInSlot.java b/rhino/src/main/java/org/mozilla/javascript/BuiltInSlot.java
index eb9777b862..32742afdbb 100644
--- a/rhino/src/main/java/org/mozilla/javascript/BuiltInSlot.java
+++ b/rhino/src/main/java/org/mozilla/javascript/BuiltInSlot.java
@@ -166,9 +166,8 @@ void setAttributes(int value) {
 
     @Override
     @SuppressWarnings("unchecked")
-    ScriptableObject getPropertyDescriptor(Context cx, Scriptable scope) {
-        return ScriptableObject.buildDataDescriptor(
-                scope, getValue((T) this.value), getAttributes());
+    DescriptorInfo getPropertyDescriptor(Context cx, Scriptable scope) {
+        return ScriptableObject.buildDataDescriptor(getValue((T) this.value), getAttributes());
     }
 
     @SuppressWarnings("unchecked")
diff --git a/rhino/src/main/java/org/mozilla/javascript/IdScriptableObject.java b/rhino/src/main/java/org/mozilla/javascript/IdScriptableObject.java
index 56870c8be4..51b6ee016e 100644
--- a/rhino/src/main/java/org/mozilla/javascript/IdScriptableObject.java
+++ b/rhino/src/main/java/org/mozilla/javascript/IdScriptableObject.java
@@ -852,20 +852,20 @@ private IdFunctionObject newIdFunction(
 
     @Override
     protected boolean defineOwnProperty(
-            Context cx, Object key, ScriptableObject desc, boolean checkValid) {
+            Context cx, Object key, DescriptorInfo desc, boolean checkValid) {
         if (key instanceof CharSequence) {
             String name = key.toString();
             int info = findInstanceIdInfo(name);
             if (info != 0) {
                 int id = (info & 0xFFFF);
-                if (isAccessorDescriptor(desc)) {
+                if (desc.isAccessorDescriptor()) {
                     delete(id); // it will be replaced with a slot
                 } else {
                     checkPropertyDefinition(desc);
                     var slot = queryOrFakeSlot(cx, key);
                     checkPropertyChangeForSlot(name, slot, desc);
                     int attr = (info >>> 16);
-                    Object value = getProperty(desc, "value");
+                    Object value = desc.value;
                     if (value != NOT_FOUND && ((attr & READONLY) == 0 || (attr & PERMANENT) == 0)) {
                         Object currentValue = getInstanceIdValue(id);
                         if (!sameValue(value, currentValue)) {
@@ -874,10 +874,7 @@ protected boolean defineOwnProperty(
                     }
                     attr =
                             applyDescriptorToAttributeBitset(
-                                    attr,
-                                    getProperty(desc, "enumerable"),
-                                    getProperty(desc, "writable"),
-                                    getProperty(desc, "configurable"));
+                                    attr, desc.enumerable, desc.writable, desc.configurable);
                     setAttributes(name, attr);
                     return true;
                 }
@@ -885,14 +882,14 @@ protected boolean defineOwnProperty(
             if (prototypeValues != null) {
                 int id = prototypeValues.findId(name);
                 if (id != 0) {
-                    if (isAccessorDescriptor(desc)) {
+                    if (desc.isAccessorDescriptor()) {
                         prototypeValues.delete(id); // it will be replaced with a slot
                     } else {
                         checkPropertyDefinition(desc);
                         var slot = queryOrFakeSlot(cx, key);
                         checkPropertyChangeForSlot(name, slot, desc);
                         int attr = prototypeValues.getAttributes(id);
-                        Object value = getProperty(desc, "value");
+                        Object value = desc.value;
                         if (value != NOT_FOUND && (attr & READONLY) == 0) {
                             Object currentValue = prototypeValues.get(id);
                             if (!sameValue(value, currentValue)) {
@@ -902,10 +899,7 @@ protected boolean defineOwnProperty(
                         prototypeValues.setAttributes(
                                 id,
                                 applyDescriptorToAttributeBitset(
-                                        attr,
-                                        getProperty(desc, "enumerable"),
-                                        getProperty(desc, "writable"),
-                                        getProperty(desc, "configurable")));
+                                        attr, desc.enumerable, desc.writable, desc.configurable));
 
                         // Handle the regular slot that was created if this property was previously
                         // replaced
@@ -923,8 +917,8 @@ protected boolean defineOwnProperty(
     }
 
     @Override
-    protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
-        ScriptableObject desc = super.getOwnPropertyDescriptor(cx, id);
+    protected DescriptorInfo getOwnPropertyDescriptor(Context cx, Object id) {
+        var desc = super.getOwnPropertyDescriptor(cx, id);
         if (desc == null) {
             if (id instanceof String) {
                 return getBuiltInDataDescriptor((String) id);
@@ -959,14 +953,9 @@ private Slot queryOrFakeSlot(Context cx, Object id) {
         return slot;
     }
 
-    private ScriptableObject getBuiltInDataDescriptor(String name) {
-        Scriptable scope = getParentScope();
-        if (scope == null) {
-            scope = this;
-        }
-
+    private DescriptorInfo getBuiltInDataDescriptor(String name) {
         var slot = getBuiltInSlot(name);
-        return slot == null ? null : buildDataDescriptor(scope, slot.value, slot.getAttributes());
+        return slot == null ? null : new DescriptorInfo(slot.value, slot.getAttributes(), true);
     }
 
     private Slot getBuiltInSlot(String name) {
@@ -992,14 +981,9 @@ private Slot getBuiltInSlot(String name) {
         return null;
     }
 
-    private ScriptableObject getBuiltInDataDescriptor(Symbol key) {
-        Scriptable scope = getParentScope();
-        if (scope == null) {
-            scope = this;
-        }
-
+    private DescriptorInfo getBuiltInDataDescriptor(Symbol key) {
         var slot = getBuiltInSlot(key);
-        return slot == null ? null : buildDataDescriptor(scope, slot.value, slot.getAttributes());
+        return slot == null ? null : new DescriptorInfo(slot.value, slot.getAttributes(), true);
     }
 
     private Slot getBuiltInSlot(Symbol key) {
diff --git a/rhino/src/main/java/org/mozilla/javascript/LambdaAccessorSlot.java b/rhino/src/main/java/org/mozilla/javascript/LambdaAccessorSlot.java
index fec3a920fb..a20f171574 100644
--- a/rhino/src/main/java/org/mozilla/javascript/LambdaAccessorSlot.java
+++ b/rhino/src/main/java/org/mozilla/javascript/LambdaAccessorSlot.java
@@ -1,5 +1,7 @@
 package org.mozilla.javascript;
 
+import org.mozilla.javascript.ScriptableObject.DescriptorInfo;
+
 /**
  * A specialized property accessor using lambda functions, similar to {@link LambdaSlot}, but allows
  * defining properties with getter and setter lambdas that require access to the owner object
@@ -60,7 +62,7 @@ boolean isSetterSlot() {
     }
 
     @Override
-    ScriptableObject getPropertyDescriptor(Context cx, Scriptable scope) {
+    DescriptorInfo getPropertyDescriptor(Context cx, Scriptable scope) {
         return buildPropertyDescriptor(cx);
     }
 
@@ -70,40 +72,36 @@ ScriptableObject getPropertyDescriptor(Context cx, Scriptable scope) {
      * it can be problematic when called from inside ThreadSafeSlotMapContainer::compute lambda
      * which can lead to deadlocks.
      */
-    public ScriptableObject buildPropertyDescriptor(Context cx) {
-        ScriptableObject desc = new NativeObject();
-
+    public DescriptorInfo buildPropertyDescriptor(Context cx) {
         int attr = getAttributes();
+        DescriptorInfo desc;
         boolean es6 = cx.getLanguageVersion() >= Context.VERSION_ES6;
         if (es6) {
+            desc = new DescriptorInfo(ScriptableObject.NOT_FOUND, attr, false);
             if (getterFunction == null && setterFunction == null) {
-                desc.defineProperty(
-                        "writable",
-                        (attr & ScriptableObject.READONLY) == 0,
-                        ScriptableObject.EMPTY);
+                desc.writable = (attr & ScriptableObject.READONLY) == 0;
             }
         } else {
-            desc.setCommonDescriptorProperties(
-                    attr, getterFunction == null && setterFunction == null);
+            desc =
+                    new DescriptorInfo(
+                            ScriptableObject.NOT_FOUND,
+                            attr,
+                            getterFunction == null && setterFunction == null);
         }
 
         if (getterFunction != null) {
-            desc.defineProperty("get", this.getterFunction, ScriptableObject.EMPTY);
+            desc.getter = this.getterFunction;
         }
 
         if (setterFunction != null) {
-            desc.defineProperty("set", this.setterFunction, ScriptableObject.EMPTY);
+            desc.setter = this.setterFunction;
         } else if (es6) {
-            desc.defineProperty("set", Undefined.instance, ScriptableObject.EMPTY);
+            desc.setter = Undefined.instance;
         }
 
         if (es6) {
-            desc.defineProperty(
-                    "enumerable", (attr & ScriptableObject.DONTENUM) == 0, ScriptableObject.EMPTY);
-            desc.defineProperty(
-                    "configurable",
-                    (attr & ScriptableObject.PERMANENT) == 0,
-                    ScriptableObject.EMPTY);
+            desc.enumerable = (attr & ScriptableObject.DONTENUM) == 0;
+            desc.configurable = (attr & ScriptableObject.PERMANENT) == 0;
         }
         return desc;
     }
diff --git a/rhino/src/main/java/org/mozilla/javascript/LambdaSlot.java b/rhino/src/main/java/org/mozilla/javascript/LambdaSlot.java
index d5fe6e11f1..f879d67ae3 100644
--- a/rhino/src/main/java/org/mozilla/javascript/LambdaSlot.java
+++ b/rhino/src/main/java/org/mozilla/javascript/LambdaSlot.java
@@ -2,6 +2,7 @@
 
 import java.util.function.Consumer;
 import java.util.function.Supplier;
+import org.mozilla.javascript.ScriptableObject.DescriptorInfo;
 
 /**
  * This is a specialization of property access using some lambda functions. It behaves exactly like
@@ -47,15 +48,8 @@ boolean isSetterSlot() {
     }
 
     @Override
-    ScriptableObject getPropertyDescriptor(Context cx, Scriptable scope) {
-        ScriptableObject desc = (ScriptableObject) cx.newObject(scope);
-        if (getter != null) {
-            desc.defineProperty("value", getter.get(), ScriptableObject.EMPTY);
-        } else {
-            desc.defineProperty("value", value, ScriptableObject.EMPTY);
-        }
-        desc.setCommonDescriptorProperties(getAttributes(), true);
-        return desc;
+    DescriptorInfo getPropertyDescriptor(Context cx, Scriptable scope) {
+        return new DescriptorInfo(getter == null ? value : getter.get(), getAttributes(), true);
     }
 
     @Override
diff --git a/rhino/src/main/java/org/mozilla/javascript/NativeArray.java b/rhino/src/main/java/org/mozilla/javascript/NativeArray.java
index bd1d2054d5..736781f99f 100644
--- a/rhino/src/main/java/org/mozilla/javascript/NativeArray.java
+++ b/rhino/src/main/java/org/mozilla/javascript/NativeArray.java
@@ -246,7 +246,7 @@ private static Object makeUnscopables(Context cx, Scriptable scope) {
 
         obj = (NativeObject) cx.newObject(scope);
 
-        ScriptableObject desc = ScriptableObject.buildDataDescriptor(obj, true, EMPTY);
+        var desc = ScriptableObject.buildDataDescriptor(true, EMPTY);
         for (var k : UNSCOPABLES) {
             obj.defineOwnProperty(cx, k, desc);
         }
@@ -464,16 +464,8 @@ public Object getDefaultValue(Class<?> hint) {
         return super.getDefaultValue(hint);
     }
 
-    private ScriptableObject defaultIndexPropertyDescriptor(Object value) {
-        Scriptable scope = getParentScope();
-        if (scope == null) scope = this;
-        ScriptableObject desc = new NativeObject();
-        ScriptRuntime.setBuiltinProtoAndParent(desc, scope, TopLevel.Builtins.Object);
-        desc.defineProperty("value", value, EMPTY);
-        desc.defineProperty("writable", Boolean.TRUE, EMPTY);
-        desc.defineProperty("enumerable", Boolean.TRUE, EMPTY);
-        desc.defineProperty("configurable", Boolean.TRUE, EMPTY);
-        return desc;
+    private DescriptorInfo defaultIndexPropertyDescriptor(Object value) {
+        return new DescriptorInfo(true, true, true, NOT_FOUND, NOT_FOUND, value);
     }
 
     @Override
@@ -485,7 +477,7 @@ public int getAttributes(int index) {
     }
 
     @Override
-    protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
+    protected DescriptorInfo getOwnPropertyDescriptor(Context cx, Object id) {
         if (dense != null) {
             int index = toDenseIndex(id);
             if (0 <= index && index < dense.length && dense[index] != NOT_FOUND) {
@@ -498,7 +490,7 @@ protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
 
     @Override
     protected boolean defineOwnProperty(
-            Context cx, Object id, ScriptableObject desc, boolean checkValid) {
+            Context cx, Object id, DescriptorInfo desc, boolean checkValid) {
         long index = toArrayIndex(id);
         if (index >= length) {
             length = index + 1;
@@ -748,9 +740,9 @@ private static Object js_of(Context cx, Scriptable scope, Scriptable thisObj, Ob
                 callConstructorOrCreateArray(cx, scope, thisObj, args.length, true);
 
         if (cx.getLanguageVersion() >= Context.VERSION_ES6 && result instanceof ScriptableObject) {
-            ScriptableObject desc = ScriptableObject.buildDataDescriptor(result, null, EMPTY);
+            var desc = ScriptableObject.buildDataDescriptor(null, EMPTY);
             for (int i = 0; i < args.length; i++) {
-                desc.put("value", desc, args[i]);
+                desc.value = args[i];
                 ((ScriptableObject) result).defineOwnProperty(cx, i, desc);
             }
         } else {
diff --git a/rhino/src/main/java/org/mozilla/javascript/NativeObject.java b/rhino/src/main/java/org/mozilla/javascript/NativeObject.java
index bba1b14198..a6bc3aece3 100644
--- a/rhino/src/main/java/org/mozilla/javascript/NativeObject.java
+++ b/rhino/src/main/java/org/mozilla/javascript/NativeObject.java
@@ -571,8 +571,8 @@ private static Object js_getOwnPropDesc(
         Scriptable s = getCompatibleObject(cx, scope, arg);
         ScriptableObject obj = ensureScriptableObject(s);
         Object nameArg = args.length < 2 ? Undefined.instance : args[1];
-        Scriptable desc = obj.getOwnPropertyDescriptor(cx, nameArg);
-        return desc == null ? Undefined.instance : desc;
+        var desc = obj.getOwnPropertyDescriptor(cx, nameArg);
+        return desc == null ? Undefined.instance : desc.toObject(scope);
     }
 
     private static Object js_getOwnPropDescs(
@@ -587,15 +587,15 @@ private static Object js_getOwnPropDescs(
             ids = obj.getIds(map, true, true);
         }
         for (Object key : ids) {
-            Scriptable desc = obj.getOwnPropertyDescriptor(cx, key);
+            var desc = obj.getOwnPropertyDescriptor(cx, key);
             if (desc == null) {
                 continue;
             } else if (key instanceof Symbol) {
-                descs.put((Symbol) key, descs, desc);
+                descs.put((Symbol) key, descs, desc.toObject(scope));
             } else if (key instanceof Integer) {
-                descs.put((Integer) key, descs, desc);
+                descs.put((Integer) key, descs, desc.toObject(scope));
             } else {
-                descs.put(ScriptRuntime.toString(key), descs, desc);
+                descs.put(ScriptRuntime.toString(key), descs, desc.toObject(scope));
             }
         }
         return descs;
@@ -607,7 +607,8 @@ private static Object js_defineProperty(
         ScriptableObject obj = ensureScriptableObject(arg);
         Object name = args.length < 2 ? Undefined.instance : args[1];
         Object descArg = args.length < 3 ? Undefined.instance : args[2];
-        ScriptableObject desc = ensureScriptableObject(descArg);
+        var desc = new DescriptorInfo(ensureScriptableObject(descArg));
+        ScriptableObject.checkPropertyDefinition(desc);
         obj.defineOwnProperty(cx, name, desc);
         return obj;
     }
diff --git a/rhino/src/main/java/org/mozilla/javascript/NativeProxy.java b/rhino/src/main/java/org/mozilla/javascript/NativeProxy.java
index cbd202db23..cb27e5e6c0 100644
--- a/rhino/src/main/java/org/mozilla/javascript/NativeProxy.java
+++ b/rhino/src/main/java/org/mozilla/javascript/NativeProxy.java
@@ -125,7 +125,7 @@ public Scriptable construct(Context cx, Scriptable scope, Object[] args) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_CONSTRUCT);
+        Function trap = getTrap(TRAP_CONSTRUCT);
         if (trap != null) {
             Object result = callTrap(trap, new Object[] {target, args, this});
             if (!(result instanceof Scriptable) || ScriptRuntime.isSymbol(result)) {
@@ -164,17 +164,16 @@ public boolean has(String name, Scriptable start) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_HAS);
+        Function trap = getTrap(TRAP_HAS);
         if (trap != null) {
 
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(callTrap(trap, new Object[] {target, name}));
             if (!booleanTrapResult) {
-                ScriptableObject targetDesc =
+                DescriptorInfo targetDesc =
                         target.getOwnPropertyDescriptor(Context.getContext(), name);
                 if (targetDesc != null) {
-                    if (Boolean.FALSE.equals(targetDesc.get("configurable"))
-                            || !target.isExtensible()) {
+                    if (targetDesc.isConfigurable(false) || !target.isExtensible()) {
                         throw ScriptRuntime.typeError(
                                 "proxy can't report an existing own property '"
                                         + name
@@ -218,17 +217,16 @@ public boolean has(int index, Scriptable start) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_HAS);
+        Function trap = getTrap(TRAP_HAS);
         if (trap != null) {
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(
                             callTrap(trap, new Object[] {target, ScriptRuntime.toString(index)}));
             if (!booleanTrapResult) {
-                ScriptableObject targetDesc =
+                DescriptorInfo targetDesc =
                         target.getOwnPropertyDescriptor(Context.getContext(), index);
                 if (targetDesc != null) {
-                    if (Boolean.FALSE.equals(targetDesc.get("configurable"))
-                            || !target.isExtensible()) {
+                    if (targetDesc.isConfigurable(false) || !target.isExtensible()) {
                         throw ScriptRuntime.typeError(
                                 "proxy can't check an existing property ' + name + ' existance on an not configurable or not extensible object");
                     }
@@ -253,16 +251,15 @@ public boolean has(int index, Scriptable start) {
     public boolean has(Symbol key, Scriptable start) {
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_HAS);
+        Function trap = getTrap(TRAP_HAS);
         if (trap != null) {
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(callTrap(trap, new Object[] {target, key}));
             if (!booleanTrapResult) {
-                ScriptableObject targetDesc =
+                DescriptorInfo targetDesc =
                         target.getOwnPropertyDescriptor(Context.getContext(), key);
                 if (targetDesc != null) {
-                    if (Boolean.FALSE.equals(targetDesc.get("configurable"))
-                            || !target.isExtensible()) {
+                    if (targetDesc.isConfigurable(false) || !target.isExtensible()) {
                         throw ScriptRuntime.typeError(
                                 "proxy can't check an existing property ' + name + ' existance on an not configurable or not extensible object");
                     }
@@ -324,7 +321,7 @@ Object[] getIds(CompoundOperationMap map, boolean getNonEnumerable, boolean getS
         */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_OWN_KEYS);
+        Function trap = getTrap(TRAP_OWN_KEYS);
         if (trap != null) {
             Object res = callTrap(trap, new Object[] {target});
             if (!(res instanceof Scriptable)) {
@@ -361,8 +358,8 @@ Object[] getIds(CompoundOperationMap map, boolean getNonEnumerable, boolean getS
             ArrayList<Object> targetConfigurableKeys = new ArrayList<>();
             ArrayList<Object> targetNonconfigurableKeys = new ArrayList<>();
             for (Object targetKey : targetKeys) {
-                ScriptableObject desc = target.getOwnPropertyDescriptor(cx, targetKey);
-                if (desc != null && Boolean.FALSE.equals(desc.get("configurable"))) {
+                DescriptorInfo desc = target.getOwnPropertyDescriptor(cx, targetKey);
+                if (desc != null && desc.isConfigurable(false)) {
                     targetNonconfigurableKeys.add(targetKey);
                 } else {
                     targetConfigurableKeys.add(targetKey);
@@ -431,24 +428,19 @@ public Object get(String name, Scriptable start) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_GET);
+        Function trap = getTrap(TRAP_GET);
         if (trap != null) {
             Object trapResult = callTrap(trap, new Object[] {target, name, this});
 
-            ScriptableObject targetDesc =
-                    target.getOwnPropertyDescriptor(Context.getContext(), name);
-            if (targetDesc != null
-                    && !Undefined.isUndefined(targetDesc)
-                    && Boolean.FALSE.equals(targetDesc.get("configurable"))) {
-                if (ScriptableObject.isDataDescriptor(targetDesc)
-                        && Boolean.FALSE.equals(targetDesc.get("writable"))) {
-                    if (!Objects.equals(trapResult, targetDesc.get("value"))) {
+            DescriptorInfo targetDesc = target.getOwnPropertyDescriptor(Context.getContext(), name);
+            if (targetDesc != null && targetDesc.isConfigurable(false)) {
+                if (targetDesc.isDataDescriptor() && targetDesc.isWritable(false)) {
+                    if (!Objects.equals(trapResult, targetDesc.value)) {
                         throw ScriptRuntime.typeError(
                                 "proxy get has to return the same value as the plain call");
                     }
                 }
-                if (ScriptableObject.isAccessorDescriptor(targetDesc)
-                        && Undefined.isUndefined(targetDesc.get("get"))) {
+                if (targetDesc.isAccessorDescriptor() && Undefined.isUndefined(targetDesc.getter)) {
                     if (!Undefined.isUndefined(trapResult)) {
                         throw ScriptRuntime.typeError(
                                 "proxy get has to return the same value as the plain call");
@@ -491,25 +483,23 @@ public Object get(int index, Scriptable start) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_GET);
+        Function trap = getTrap(TRAP_GET);
         if (trap != null) {
             Object trapResult =
                     callTrap(trap, new Object[] {target, ScriptRuntime.toString(index), this});
 
-            ScriptableObject targetDesc =
+            DescriptorInfo targetDesc =
                     target.getOwnPropertyDescriptor(Context.getContext(), index);
             if (targetDesc != null
                     && !Undefined.isUndefined(targetDesc)
-                    && Boolean.FALSE.equals(targetDesc.get("configurable"))) {
-                if (ScriptableObject.isDataDescriptor(targetDesc)
-                        && Boolean.FALSE.equals(targetDesc.get("writable"))) {
-                    if (!Objects.equals(trapResult, targetDesc.get("value"))) {
+                    && targetDesc.isConfigurable(false)) {
+                if (targetDesc.isDataDescriptor() && targetDesc.isWritable(false)) {
+                    if (!Objects.equals(trapResult, targetDesc.value)) {
                         throw ScriptRuntime.typeError(
                                 "proxy get has to return the same value as the plain call");
                     }
                 }
-                if (ScriptableObject.isAccessorDescriptor(targetDesc)
-                        && Undefined.isUndefined(targetDesc.get("get"))) {
+                if (targetDesc.isAccessorDescriptor() && Undefined.isUndefined(targetDesc.getter)) {
                     if (!Undefined.isUndefined(trapResult)) {
                         throw ScriptRuntime.typeError(
                                 "proxy get has to return the same value as the plain call");
@@ -552,24 +542,21 @@ public Object get(Symbol key, Scriptable start) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_GET);
+        Function trap = getTrap(TRAP_GET);
         if (trap != null) {
             Object trapResult = callTrap(trap, new Object[] {target, key, this});
 
-            ScriptableObject targetDesc =
-                    target.getOwnPropertyDescriptor(Context.getContext(), key);
+            DescriptorInfo targetDesc = target.getOwnPropertyDescriptor(Context.getContext(), key);
             if (targetDesc != null
                     && !Undefined.isUndefined(targetDesc)
-                    && Boolean.FALSE.equals(targetDesc.get("configurable"))) {
-                if (ScriptableObject.isDataDescriptor(targetDesc)
-                        && Boolean.FALSE.equals(targetDesc.get("writable"))) {
-                    if (!Objects.equals(trapResult, targetDesc.get("value"))) {
+                    && targetDesc.isConfigurable(false)) {
+                if (targetDesc.isDataDescriptor() && targetDesc.isWritable(false)) {
+                    if (!Objects.equals(trapResult, targetDesc.value)) {
                         throw ScriptRuntime.typeError(
                                 "proxy get has to return the same value as the plain call");
                     }
                 }
-                if (ScriptableObject.isAccessorDescriptor(targetDesc)
-                        && Undefined.isUndefined(targetDesc.get("get"))) {
+                if (targetDesc.isAccessorDescriptor() && Undefined.isUndefined(targetDesc.getter)) {
                     if (!Undefined.isUndefined(trapResult)) {
                         throw ScriptRuntime.typeError(
                                 "proxy get has to return the same value as the plain call");
@@ -614,7 +601,7 @@ public void put(String name, Scriptable start, Object value) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_SET);
+        Function trap = getTrap(TRAP_SET);
         if (trap != null) {
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(callTrap(trap, new Object[] {target, name, value}));
@@ -622,20 +609,17 @@ public void put(String name, Scriptable start, Object value) {
                 return; // false
             }
 
-            ScriptableObject targetDesc =
-                    target.getOwnPropertyDescriptor(Context.getContext(), name);
+            DescriptorInfo targetDesc = target.getOwnPropertyDescriptor(Context.getContext(), name);
             if (targetDesc != null
                     && !Undefined.isUndefined(targetDesc)
-                    && Boolean.FALSE.equals(targetDesc.get("configurable"))) {
-                if (ScriptableObject.isDataDescriptor(targetDesc)
-                        && Boolean.FALSE.equals(targetDesc.get("writable"))) {
-                    if (!Objects.equals(value, targetDesc.get("value"))) {
+                    && targetDesc.isConfigurable(false)) {
+                if (targetDesc.isDataDescriptor() && targetDesc.isWritable(false)) {
+                    if (!Objects.equals(value, targetDesc.value)) {
                         throw ScriptRuntime.typeError(
                                 "proxy set has to use the same value as the plain call");
                     }
                 }
-                if (ScriptableObject.isAccessorDescriptor(targetDesc)
-                        && Undefined.isUndefined(targetDesc.get("set"))) {
+                if (targetDesc.isAccessorDescriptor() && Undefined.isUndefined(targetDesc.setter)) {
                     throw ScriptRuntime.typeError("proxy set has to be available");
                 }
             }
@@ -676,7 +660,7 @@ public void put(int index, Scriptable start, Object value) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_SET);
+        Function trap = getTrap(TRAP_SET);
         if (trap != null) {
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(
@@ -687,20 +671,18 @@ public void put(int index, Scriptable start, Object value) {
                 return; // false
             }
 
-            ScriptableObject targetDesc =
+            DescriptorInfo targetDesc =
                     target.getOwnPropertyDescriptor(Context.getContext(), index);
             if (targetDesc != null
                     && !Undefined.isUndefined(targetDesc)
-                    && Boolean.FALSE.equals(targetDesc.get("configurable"))) {
-                if (ScriptableObject.isDataDescriptor(targetDesc)
-                        && Boolean.FALSE.equals(targetDesc.get("writable"))) {
-                    if (!Objects.equals(value, targetDesc.get("value"))) {
+                    && targetDesc.isConfigurable(false)) {
+                if (targetDesc.isDataDescriptor() && targetDesc.isWritable(false)) {
+                    if (!Objects.equals(value, targetDesc.value)) {
                         throw ScriptRuntime.typeError(
                                 "proxy set has to use the same value as the plain call");
                     }
                 }
-                if (ScriptableObject.isAccessorDescriptor(targetDesc)
-                        && Undefined.isUndefined(targetDesc.get("set"))) {
+                if (targetDesc.isAccessorDescriptor() && Undefined.isUndefined(targetDesc.setter)) {
                     throw ScriptRuntime.typeError("proxy set has to be available");
                 }
             }
@@ -741,7 +723,7 @@ public void put(Symbol key, Scriptable start, Object value) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_SET);
+        Function trap = getTrap(TRAP_SET);
         if (trap != null) {
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(callTrap(trap, new Object[] {target, key, value}));
@@ -749,20 +731,17 @@ public void put(Symbol key, Scriptable start, Object value) {
                 return; // false
             }
 
-            ScriptableObject targetDesc =
-                    target.getOwnPropertyDescriptor(Context.getContext(), key);
+            DescriptorInfo targetDesc = target.getOwnPropertyDescriptor(Context.getContext(), key);
             if (targetDesc != null
                     && !Undefined.isUndefined(targetDesc)
-                    && Boolean.FALSE.equals(targetDesc.get("configurable"))) {
-                if (ScriptableObject.isDataDescriptor(targetDesc)
-                        && Boolean.FALSE.equals(targetDesc.get("writable"))) {
-                    if (!Objects.equals(value, targetDesc.get("value"))) {
+                    && targetDesc.isConfigurable(false)) {
+                if (targetDesc.isDataDescriptor() && targetDesc.isWritable(false)) {
+                    if (!Objects.equals(value, targetDesc.value)) {
                         throw ScriptRuntime.typeError(
                                 "proxy set has to use the same value as the plain call");
                     }
                 }
-                if (ScriptableObject.isAccessorDescriptor(targetDesc)
-                        && Undefined.isUndefined(targetDesc.get("set"))) {
+                if (targetDesc.isAccessorDescriptor() && Undefined.isUndefined(targetDesc.setter)) {
                     throw ScriptRuntime.typeError("proxy set has to be available");
                 }
             }
@@ -803,7 +782,7 @@ public void delete(String name) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_DELETE_PROPERTY);
+        Function trap = getTrap(TRAP_DELETE_PROPERTY);
         if (trap != null) {
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(callTrap(trap, new Object[] {target, name}));
@@ -811,12 +790,11 @@ public void delete(String name) {
                 return; // false
             }
 
-            ScriptableObject targetDesc =
-                    target.getOwnPropertyDescriptor(Context.getContext(), name);
+            DescriptorInfo targetDesc = target.getOwnPropertyDescriptor(Context.getContext(), name);
             if (targetDesc == null) {
                 return; // true
             }
-            if (Boolean.FALSE.equals(targetDesc.get("configurable")) || !target.isExtensible()) {
+            if (targetDesc.isConfigurable(false) || !target.isExtensible()) {
                 throw ScriptRuntime.typeError(
                         "proxy can't delete an existing own property ' + name + ' on an not configurable or not extensible object");
             }
@@ -854,7 +832,7 @@ public void delete(int index) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_DELETE_PROPERTY);
+        Function trap = getTrap(TRAP_DELETE_PROPERTY);
         if (trap != null) {
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(
@@ -863,12 +841,12 @@ public void delete(int index) {
                 return; // false
             }
 
-            ScriptableObject targetDesc =
+            DescriptorInfo targetDesc =
                     target.getOwnPropertyDescriptor(Context.getContext(), index);
             if (targetDesc == null) {
                 return; // true
             }
-            if (Boolean.FALSE.equals(targetDesc.get("configurable")) || !target.isExtensible()) {
+            if (targetDesc.isConfigurable(false) || !target.isExtensible()) {
                 throw ScriptRuntime.typeError(
                         "proxy can't delete an existing own property ' + name + ' on an not configurable or not extensible object");
             }
@@ -906,7 +884,7 @@ public void delete(Symbol key) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_DELETE_PROPERTY);
+        Function trap = getTrap(TRAP_DELETE_PROPERTY);
         if (trap != null) {
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(callTrap(trap, new Object[] {target, key}));
@@ -914,12 +892,11 @@ public void delete(Symbol key) {
                 return; // false
             }
 
-            ScriptableObject targetDesc =
-                    target.getOwnPropertyDescriptor(Context.getContext(), key);
+            DescriptorInfo targetDesc = target.getOwnPropertyDescriptor(Context.getContext(), key);
             if (targetDesc == null) {
                 return; // true
             }
-            if (Boolean.FALSE.equals(targetDesc.get("configurable")) || !target.isExtensible()) {
+            if (targetDesc.isConfigurable(false) || !target.isExtensible()) {
                 throw ScriptRuntime.typeError(
                         "proxy can't delete an existing own property ' + name + ' on an not configurable or not extensible object");
             }
@@ -937,7 +914,7 @@ public void delete(Symbol key) {
      * [[GetOwnProperty]] (P)</a>
      */
     @Override
-    protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
+    protected DescriptorInfo getOwnPropertyDescriptor(Context cx, Object id) {
         /*
          * 1. Assert: IsPropertyKey(P) is true.
          * 2. Let handler be O.[[ProxyHandler]].
@@ -970,7 +947,7 @@ protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_GET_OWN_PROPERTY_DESCRIPTOR);
+        Function trap = getTrap(TRAP_GET_OWN_PROPERTY_DESCRIPTOR);
         if (trap != null) {
             Object trapResultObj = callTrap(trap, new Object[] {target, id});
             if (!Undefined.isUndefined(trapResultObj)
@@ -980,20 +957,17 @@ protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
                         "getOwnPropertyDescriptor trap has to return undefined or an object");
             }
 
-            ScriptableObject targetDesc;
-            if (ScriptRuntime.isSymbol(id)) {
-                targetDesc = target.getOwnPropertyDescriptor(cx, id);
-            } else {
-                targetDesc = target.getOwnPropertyDescriptor(cx, ScriptRuntime.toString(id));
-            }
+            var targetDesc =
+                    ScriptRuntime.isSymbol(id)
+                            ? target.getOwnPropertyDescriptor(cx, id)
+                            : target.getOwnPropertyDescriptor(cx, ScriptRuntime.toString(id));
 
             if (Undefined.isUndefined(trapResultObj)) {
                 if (Undefined.isUndefined(targetDesc)) {
                     return null;
                 }
 
-                if (Boolean.FALSE.equals(targetDesc.get("configurable"))
-                        || !target.isExtensible()) {
+                if (targetDesc.isConfigurable(false) || !target.isExtensible()) {
                     throw ScriptRuntime.typeError(
                             "proxy can't report an existing own property '"
                                     + id
@@ -1012,8 +986,7 @@ protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
                                 getProperty(trapResult, "writable"),
                                 getProperty(trapResult, "configurable"));
 
-                ScriptableObject desc =
-                        ScriptableObject.buildDataDescriptor(target, value, attributes);
+                var desc = ScriptableObject.buildDataDescriptor(value, attributes);
                 return desc;
             }
             return null;
@@ -1032,7 +1005,7 @@ protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
      * [[DefineOwnProperty]] (P, Desc)</a>
      */
     @Override
-    public boolean defineOwnProperty(Context cx, Object id, ScriptableObject desc) {
+    public boolean defineOwnProperty(Context cx, Object id, DescriptorInfo desc) {
         /*
          * 1. Assert: IsPropertyKey(P) is true.
          * 2. Let handler be O.[[ProxyHandler]].
@@ -1062,20 +1035,23 @@ public boolean defineOwnProperty(Context cx, Object id, ScriptableObject desc) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_DEFINE_PROPERTY);
+        Function trap = getTrap(TRAP_DEFINE_PROPERTY);
         if (trap != null) {
             boolean booleanTrapResult =
-                    ScriptRuntime.toBoolean(callTrap(trap, new Object[] {target, id, desc}));
+                    ScriptRuntime.toBoolean(
+                            callTrap(
+                                    trap,
+                                    new Object[] {
+                                        target, id, desc.toObject(trap.getDeclarationScope())
+                                    }));
             if (!booleanTrapResult) {
                 return false;
             }
 
-            ScriptableObject targetDesc = target.getOwnPropertyDescriptor(Context.getContext(), id);
+            DescriptorInfo targetDesc = target.getOwnPropertyDescriptor(Context.getContext(), id);
             boolean extensibleTarget = target.isExtensible();
 
-            boolean settingConfigFalse =
-                    Boolean.TRUE.equals(ScriptableObject.hasProperty(desc, "configurable"))
-                            && Boolean.FALSE.equals(desc.get("configurable"));
+            boolean settingConfigFalse = desc.isConfigurable(false);
 
             if (targetDesc == null) {
                 if (!extensibleTarget || settingConfigFalse) {
@@ -1089,16 +1065,15 @@ public boolean defineOwnProperty(Context cx, Object id, ScriptableObject desc) {
                             "proxy can't define an incompatible property descriptor");
                 }
 
-                if (settingConfigFalse && Boolean.TRUE.equals(targetDesc.get("configurable"))) {
+                if (settingConfigFalse && targetDesc.isConfigurable()) {
                     throw ScriptRuntime.typeError(
                             "proxy can't define an incompatible property descriptor");
                 }
 
-                if (ScriptableObject.isDataDescriptor(targetDesc)
-                        && Boolean.FALSE.equals(targetDesc.get("configurable"))
-                        && Boolean.TRUE.equals(targetDesc.get("writable"))) {
-                    if (Boolean.TRUE.equals(ScriptableObject.hasProperty(desc, "writable"))
-                            && Boolean.FALSE.equals(desc.get("writable"))) {
+                if (targetDesc.isDataDescriptor()
+                        && targetDesc.isConfigurable(false)
+                        && targetDesc.isWritable()) {
+                    if (desc.isWritable(false)) {
                         throw ScriptRuntime.typeError(
                                 "proxy can't define an incompatible property descriptor");
                     }
@@ -1132,7 +1107,7 @@ public boolean isExtensible() {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_IS_EXTENSIBLE);
+        Function trap = getTrap(TRAP_IS_EXTENSIBLE);
         if (trap == null) {
             return target.isExtensible();
         }
@@ -1168,7 +1143,7 @@ public boolean preventExtensions() {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_PREVENT_EXTENSIONS);
+        Function trap = getTrap(TRAP_PREVENT_EXTENSIONS);
         if (trap == null) {
             return target.preventExtensions();
         }
@@ -1210,7 +1185,7 @@ public Scriptable getPrototype() {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_GET_PROTOTYPE_OF);
+        Function trap = getTrap(TRAP_GET_PROTOTYPE_OF);
         if (trap != null) {
             Object handlerProto = callTrap(trap, new Object[] {target});
 
@@ -1267,7 +1242,7 @@ public void setPrototype(Scriptable prototype) {
          */
         ScriptableObject target = getTargetThrowIfRevoked();
 
-        Callable trap = getTrap(TRAP_SET_PROTOTYPE_OF);
+        Function trap = getTrap(TRAP_SET_PROTOTYPE_OF);
         if (trap != null) {
             boolean booleanTrapResult =
                     ScriptRuntime.toBoolean(callTrap(trap, new Object[] {target, prototype}));
@@ -1306,7 +1281,7 @@ public Object call(Context cx, Scriptable scope, Scriptable thisObj, Object[] ar
 
         Scriptable argumentsList = cx.newArray(scope, args);
 
-        Callable trap = getTrap(TRAP_APPLY);
+        Function trap = getTrap(TRAP_APPLY);
         if (trap != null) {
             return callTrap(trap, new Object[] {target, thisObj, argumentsList});
         }
@@ -1357,7 +1332,7 @@ private static Object revocable(
         return revocable;
     }
 
-    private Callable getTrap(String trapName) {
+    private Function getTrap(String trapName) {
         Object handlerProp = ScriptableObject.getProperty(handlerObj, trapName);
         if (Scriptable.NOT_FOUND == handlerProp) {
             return null;
@@ -1369,11 +1344,11 @@ private Callable getTrap(String trapName) {
             throw ScriptRuntime.notFunctionError(handlerProp, trapName);
         }
 
-        return (Callable) handlerProp;
+        return (Function) handlerProp;
     }
 
-    private Object callTrap(Callable trap, Object[] args) {
-        return trap.call(Context.getContext(), handlerObj, handlerObj, args);
+    private Object callTrap(Function trap, Object[] args) {
+        return trap.call(Context.getContext(), trap.getDeclarationScope(), handlerObj, args);
     }
 
     ScriptableObject getTargetThrowIfRevoked() {
diff --git a/rhino/src/main/java/org/mozilla/javascript/NativeReflect.java b/rhino/src/main/java/org/mozilla/javascript/NativeReflect.java
index 177fb86015..94dde4c832 100644
--- a/rhino/src/main/java/org/mozilla/javascript/NativeReflect.java
+++ b/rhino/src/main/java/org/mozilla/javascript/NativeReflect.java
@@ -171,7 +171,7 @@ private static Object defineProperty(
         }
 
         ScriptableObject target = checkTarget(args);
-        ScriptableObject desc = ScriptableObject.ensureScriptableObject(args[2]);
+        DescriptorInfo desc = new DescriptorInfo(ScriptableObject.ensureScriptableObject(args[2]));
 
         Object key = args[1];
 
@@ -229,13 +229,12 @@ private static Scriptable getOwnPropertyDescriptor(
 
         if (args.length > 1) {
             if (ScriptRuntime.isSymbol(args[1])) {
-                ScriptableObject desc = target.getOwnPropertyDescriptor(cx, args[1]);
-                return desc == null ? Undefined.SCRIPTABLE_UNDEFINED : desc;
+                var desc = target.getOwnPropertyDescriptor(cx, args[1]);
+                return desc == null ? Undefined.SCRIPTABLE_UNDEFINED : desc.toObject(scope);
             }
 
-            ScriptableObject desc =
-                    target.getOwnPropertyDescriptor(cx, ScriptRuntime.toString(args[1]));
-            return desc == null ? Undefined.SCRIPTABLE_UNDEFINED : desc;
+            var desc = target.getOwnPropertyDescriptor(cx, ScriptRuntime.toString(args[1]));
+            return desc == null ? Undefined.SCRIPTABLE_UNDEFINED : desc.toObject(scope);
         }
         return Undefined.SCRIPTABLE_UNDEFINED;
     }
@@ -308,15 +307,15 @@ private static Object set(Context cx, Scriptable scope, Scriptable thisObj, Obje
         ScriptableObject receiver =
                 args.length > 3 ? ScriptableObject.ensureScriptableObject(args[3]) : target;
         if (receiver != target) {
-            ScriptableObject descriptor = target.getOwnPropertyDescriptor(cx, args[1]);
+            DescriptorInfo descriptor = target.getOwnPropertyDescriptor(cx, args[1]);
             if (descriptor != null) {
-                Object setter = descriptor.get("set");
+                Object setter = descriptor.setter;
                 if (setter != null && setter != NOT_FOUND) {
                     ((Function) setter).call(cx, scope, receiver, new Object[] {args[2]});
                     return true;
                 }
 
-                if (Boolean.FALSE.equals(descriptor.get("configurable"))) {
+                if (descriptor.isConfigurable(false)) {
                     return false;
                 }
             }
diff --git a/rhino/src/main/java/org/mozilla/javascript/NativeString.java b/rhino/src/main/java/org/mozilla/javascript/NativeString.java
index 2e03bf0030..90a8b9a9d7 100644
--- a/rhino/src/main/java/org/mozilla/javascript/NativeString.java
+++ b/rhino/src/main/java/org/mozilla/javascript/NativeString.java
@@ -561,7 +561,7 @@ protected Object[] getIds(CompoundOperationMap map, boolean nonEnumerable, boole
     }
 
     @Override
-    protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
+    protected ScriptableObject.DescriptorInfo getOwnPropertyDescriptor(Context cx, Object id) {
         if (!(id instanceof Symbol)
                 && (cx != null)
                 && (cx.getLanguageVersion() >= Context.VERSION_ES6)) {
@@ -574,16 +574,8 @@ protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
         return super.getOwnPropertyDescriptor(cx, id);
     }
 
-    private ScriptableObject defaultIndexPropertyDescriptor(Object value) {
-        Scriptable scope = getParentScope();
-        if (scope == null) scope = this;
-        ScriptableObject desc = new NativeObject();
-        ScriptRuntime.setBuiltinProtoAndParent(desc, scope, TopLevel.Builtins.Object);
-        desc.defineProperty("value", value, EMPTY);
-        desc.defineProperty("writable", Boolean.FALSE, EMPTY);
-        desc.defineProperty("enumerable", Boolean.TRUE, EMPTY);
-        desc.defineProperty("configurable", Boolean.FALSE, EMPTY);
-        return desc;
+    private ScriptableObject.DescriptorInfo defaultIndexPropertyDescriptor(Object value) {
+        return new ScriptableObject.DescriptorInfo(true, false, false, NOT_FOUND, NOT_FOUND, value);
     }
 
     /*
diff --git a/rhino/src/main/java/org/mozilla/javascript/ScriptRuntimeES6.java b/rhino/src/main/java/org/mozilla/javascript/ScriptRuntimeES6.java
index a151b7e8d3..0d81061c52 100644
--- a/rhino/src/main/java/org/mozilla/javascript/ScriptRuntimeES6.java
+++ b/rhino/src/main/java/org/mozilla/javascript/ScriptRuntimeES6.java
@@ -6,6 +6,8 @@
 
 package org.mozilla.javascript;
 
+import org.mozilla.javascript.ScriptableObject.DescriptorInfo;
+
 public class ScriptRuntimeES6 {
 
     public static Object requireObjectCoercible(
@@ -30,20 +32,23 @@ public static Object requireObjectCoercible(
     /** Registers the symbol {@code [Symbol.species]} on the given constructor function. */
     public static void addSymbolSpecies(
             Context cx, Scriptable scope, ScriptableObject constructor) {
-        ScriptableObject speciesDescriptor = (ScriptableObject) cx.newObject(scope);
-        ScriptableObject.putProperty(speciesDescriptor, "enumerable", false);
-        ScriptableObject.putProperty(speciesDescriptor, "configurable", true);
-        ScriptableObject.putProperty(
-                speciesDescriptor,
-                "get",
-                new LambdaFunction(
-                        scope,
-                        "get [Symbol.species]",
-                        0,
-                        (Context lcx, Scriptable lscope, Scriptable thisObj, Object[] args) ->
-                                thisObj,
-                        false));
-        constructor.defineOwnProperty(cx, SymbolKey.SPECIES, speciesDescriptor, false);
+        DescriptorInfo desc =
+                new DescriptorInfo(
+                        false,
+                        ScriptableObject.NOT_FOUND,
+                        true,
+                        new LambdaFunction(
+                                scope,
+                                "get [Symbol.species]",
+                                0,
+                                (Context lcx,
+                                        Scriptable lscope,
+                                        Scriptable thisObj,
+                                        Object[] args) -> thisObj,
+                                false),
+                        ScriptableObject.NOT_FOUND,
+                        ScriptableObject.NOT_FOUND);
+        constructor.defineOwnProperty(cx, SymbolKey.SPECIES, desc, false);
     }
 
     /** Registers the symbol {@code [Symbol.unscopables]} on the given constructor function. */
diff --git a/rhino/src/main/java/org/mozilla/javascript/ScriptableObject.java b/rhino/src/main/java/org/mozilla/javascript/ScriptableObject.java
index c0dc49be44..b0408dfbc3 100644
--- a/rhino/src/main/java/org/mozilla/javascript/ScriptableObject.java
+++ b/rhino/src/main/java/org/mozilla/javascript/ScriptableObject.java
@@ -127,13 +127,8 @@ public abstract class ScriptableObject extends SlotMapOwner
         }
     }
 
-    protected static ScriptableObject buildDataDescriptor(
-            Scriptable scope, Object value, int attributes) {
-        ScriptableObject desc = new NativeObject();
-        ScriptRuntime.setBuiltinProtoAndParent(desc, scope, TopLevel.Builtins.Object);
-        desc.defineProperty("value", value, EMPTY);
-        desc.setCommonDescriptorProperties(attributes, true);
-        return desc;
+    protected static DescriptorInfo buildDataDescriptor(Object value, int attributes) {
+        return new DescriptorInfo(value, attributes, true);
     }
 
     protected void setCommonDescriptorProperties(int attributes, boolean defineWritable) {
@@ -1637,10 +1632,10 @@ public void defineOwnProperties(Context cx, ScriptableObject props) {
         try (var map = props.startCompoundOp(false)) {
             ids = props.getIds(map, false, true);
         }
-        ScriptableObject[] descs = new ScriptableObject[ids.length];
+        DescriptorInfo[] descs = new DescriptorInfo[ids.length];
         for (int i = 0, len = ids.length; i < len; ++i) {
             Object descObj = ScriptRuntime.getObjectElem(props, ids[i], cx);
-            ScriptableObject desc = ensureScriptableObject(descObj);
+            var desc = new DescriptorInfo(ensureScriptableObject(descObj));
             checkPropertyDefinition(desc);
             descs[i] = desc;
         }
@@ -1658,6 +1653,10 @@ public void defineOwnProperties(Context cx, ScriptableObject props) {
      */
     public boolean defineOwnProperty(Context cx, Object id, ScriptableObject desc) {
         checkPropertyDefinition(desc);
+        return defineOwnProperty(cx, id, new DescriptorInfo(desc), true);
+    }
+
+    public boolean defineOwnProperty(Context cx, Object id, DescriptorInfo desc) {
         return defineOwnProperty(cx, id, desc, true);
     }
 
@@ -1674,7 +1673,7 @@ public boolean defineOwnProperty(Context cx, Object id, ScriptableObject desc) {
      * @return always true at the moment
      */
     protected boolean defineOwnProperty(
-            Context cx, Object id, ScriptableObject desc, boolean checkValid) {
+            Context cx, Object id, DescriptorInfo desc, boolean checkValid) {
 
         Object key = null;
         int index = 0;
@@ -1691,11 +1690,6 @@ protected boolean defineOwnProperty(
 
         Slot aSlot = getMap().query(key, index);
 
-        // We convert the whole object to a descriptor at this point
-        // because we have no good way to reliably to do so inside a
-        // compound operation.
-        var info = new DescriptorInfo(desc);
-
         if (aSlot instanceof BuiltInSlot) {
             // 10.4.2.4 ArrayLengthSet requires we check that any new
             // value is valid and throw a range error if not before
@@ -1708,7 +1702,7 @@ protected boolean defineOwnProperty(
             // modify the current descriptor as part of operations
             // performed as part of applying the descriptor.
 
-            return ((BuiltInSlot<?>) aSlot).applyNewDescriptor(id, info, checkValid, key, index);
+            return ((BuiltInSlot<?>) aSlot).applyNewDescriptor(id, desc, checkValid, key, index);
         } else {
             try (var map = startCompoundOp(true)) {
                 return defineOrdinaryProperty(
@@ -1716,7 +1710,7 @@ protected boolean defineOwnProperty(
                         this,
                         map,
                         id,
-                        info,
+                        desc,
                         checkValid,
                         key,
                         index);
@@ -1725,15 +1719,15 @@ protected boolean defineOwnProperty(
     }
 
     public static final class DescriptorInfo {
-        Object enumerable;
-        Object writable;
-        Object configurable;
-        Object getter;
-        Object setter;
-        Object value;
+        public Object enumerable = NOT_FOUND;
+        public Object writable = NOT_FOUND;
+        public Object configurable = NOT_FOUND;
+        public Object getter = NOT_FOUND;
+        public Object setter = NOT_FOUND;
+        public Object value = NOT_FOUND;
         boolean accessorDescriptor;
 
-        DescriptorInfo(ScriptableObject desc) {
+        public DescriptorInfo(ScriptableObject desc) {
             enumerable = getProperty(desc, "enumerable");
             writable = getProperty(desc, "writable");
             configurable = getProperty(desc, "configurable");
@@ -1742,6 +1736,114 @@ public static final class DescriptorInfo {
             value = getProperty(desc, "value");
             accessorDescriptor = getter != NOT_FOUND || setter != NOT_FOUND;
         }
+
+        public DescriptorInfo(
+                boolean enumerable, boolean writable, boolean configurable, Object value) {
+            this.enumerable = enumerable;
+            this.writable = writable;
+            this.configurable = configurable;
+            this.getter = NOT_FOUND;
+            this.setter = NOT_FOUND;
+            this.value = value;
+            accessorDescriptor = false;
+        }
+
+        public DescriptorInfo(
+                Object enumerable,
+                Object writable,
+                Object configurable,
+                Object getter,
+                Object setter,
+                Object value) {
+            this.enumerable = enumerable;
+            this.writable = writable;
+            this.configurable = configurable;
+            this.getter = getter;
+            this.setter = setter;
+            this.value = value;
+            accessorDescriptor = getter != NOT_FOUND || setter != NOT_FOUND;
+        }
+
+        DescriptorInfo(Object value, int attributes, boolean defineWritable) {
+            this.value = value;
+            if (defineWritable) {
+                writable = (attributes & READONLY) == 0;
+            }
+            enumerable = (attributes & DONTENUM) == 0;
+            configurable = (attributes & PERMANENT) == 0;
+        }
+
+        Scriptable toObject(Scriptable scope) {
+            ScriptableObject desc = new NativeObject();
+            ScriptRuntime.setBuiltinProtoAndParent(desc, scope, TopLevel.Builtins.Object);
+            if (hasValue()) desc.defineProperty("value", value, EMPTY);
+            if (hasWritable()) desc.defineProperty("writable", writable, EMPTY);
+            if (hasGetter()) desc.defineProperty("get", getter, EMPTY);
+            if (hasSetter()) desc.defineProperty("set", setter, EMPTY);
+            if (hasEnumerable()) desc.defineProperty("enumerable", enumerable, EMPTY);
+            if (hasConfigurable()) desc.defineProperty("configurable", configurable, EMPTY);
+            return desc;
+        }
+
+        public boolean isWritable() {
+            return Boolean.TRUE.equals(writable);
+        }
+
+        public boolean isWritable(boolean value) {
+            return ((Boolean) value).equals(writable);
+        }
+
+        public boolean hasWritable() {
+            return writable != NOT_FOUND;
+        }
+
+        public boolean isEnumerable() {
+            return Boolean.TRUE.equals(enumerable);
+        }
+
+        public boolean isEnumerable(boolean value) {
+            return ((Boolean) value).equals(enumerable);
+        }
+
+        public boolean hasEnumerable() {
+            return enumerable != NOT_FOUND;
+        }
+
+        public boolean isConfigurable() {
+            return Boolean.TRUE.equals(configurable);
+        }
+
+        public boolean isConfigurable(boolean value) {
+            return ((Boolean) value).equals(configurable);
+        }
+
+        public boolean hasConfigurable() {
+            return configurable != NOT_FOUND;
+        }
+
+        public boolean hasValue() {
+            return value != NOT_FOUND;
+        }
+
+        public boolean hasGetter() {
+            return getter != NOT_FOUND;
+        }
+
+        public boolean hasSetter() {
+            return setter != NOT_FOUND;
+        }
+
+        public boolean isDataDescriptor() {
+            return hasValue() || hasWritable();
+        }
+
+        public boolean isAccessorDescriptor() {
+            return hasGetter() || hasSetter();
+        }
+
+        public boolean isGenericDescriptor() {
+            return !isDataDescriptor() && !isAccessorDescriptor();
+        }
     }
 
     static boolean defineOrdinaryProperty(
@@ -1838,7 +1940,7 @@ static Slot setSlotValue(
                 ((BuiltInSlot<?>) slot).setValueFromDescriptor(info.value, owner, owner, true);
             }
         } else {
-            if (!slot.isValueSlot() && isDataDescriptor(info)) {
+            if (!slot.isValueSlot() && info.isDataDescriptor()) {
                 // Replace a non-base slot with a regular slot
                 slot = new Slot(slot);
             }
@@ -1942,7 +2044,7 @@ public void defineProperty(
     }
 
     private void replaceLambdaAccessorSlot(Context cx, Object key, LambdaAccessorSlot newSlot) {
-        ScriptableObject newDesc = newSlot.buildPropertyDescriptor(cx);
+        var newDesc = newSlot.buildPropertyDescriptor(cx);
         checkPropertyDefinition(newDesc);
         getMap().compute(
                         this,
@@ -1989,7 +2091,7 @@ private LambdaAccessorSlot createLambdaAccessorSlot(
         return slot;
     }
 
-    protected void checkPropertyDefinition(ScriptableObject desc) {
+    protected static void checkPropertyDefinition(ScriptableObject desc) {
         Object getter = getProperty(desc, "get");
         if (getter != NOT_FOUND && getter != Undefined.instance && !(getter instanceof Callable)) {
             throw ScriptRuntime.notFunctionError(getter);
@@ -2003,6 +2105,20 @@ protected void checkPropertyDefinition(ScriptableObject desc) {
         }
     }
 
+    protected static void checkPropertyDefinition(DescriptorInfo desc) {
+        Object getter = desc.getter;
+        if (getter != NOT_FOUND && getter != Undefined.instance && !(getter instanceof Callable)) {
+            throw ScriptRuntime.notFunctionError(getter);
+        }
+        Object setter = desc.setter;
+        if (setter != NOT_FOUND && setter != Undefined.instance && !(setter instanceof Callable)) {
+            throw ScriptRuntime.notFunctionError(setter);
+        }
+        if (desc.isDataDescriptor() && desc.isAccessorDescriptor()) {
+            throw ScriptRuntime.typeErrorById("msg.both.data.and.accessor.desc");
+        }
+    }
+
     protected final void checkPropertyChangeForSlot(
             Object id, Slot current, ScriptableObject desc) {
         checkPropertyChangeForSlot(id, current, new DescriptorInfo(desc));
@@ -2019,7 +2135,7 @@ protected final void checkPropertyChangeForSlot(Object id, Slot current, Descrip
                 if (((current.getAttributes() & DONTENUM) == 0) != isTrue(info.enumerable))
                     throw ScriptRuntime.typeErrorById(
                             "msg.change.enumerable.with.configurable.false", id);
-                boolean isData = isDataDescriptor(info);
+                boolean isData = info.isDataDescriptor();
                 boolean isBuiltIn = current instanceof BuiltInSlot;
                 boolean isAccessor = info.accessorDescriptor;
                 if (!isData && !isAccessor) {
@@ -2128,10 +2244,6 @@ protected static boolean isDataDescriptor(ScriptableObject desc) {
         return hasProperty(desc, "value") || hasProperty(desc, "writable");
     }
 
-    protected static boolean isDataDescriptor(DescriptorInfo info) {
-        return info.value != NOT_FOUND || info.writable != NOT_FOUND;
-    }
-
     /**
      * Implements IsAccessorDescriptor as described in ES5 8.10.1
      *
@@ -2142,6 +2254,10 @@ protected static boolean isAccessorDescriptor(ScriptableObject desc) {
         return hasProperty(desc, "get") || hasProperty(desc, "set");
     }
 
+    protected static boolean isAccessorDescriptor(DescriptorInfo desc) {
+        return desc.hasGetter() || desc.hasSetter();
+    }
+
     /**
      * Implements IsGenericDescriptor as described in ES5 8.10.3
      *
@@ -2152,6 +2268,10 @@ protected static boolean isGenericDescriptor(ScriptableObject desc) {
         return !isDataDescriptor(desc) && !isAccessorDescriptor(desc);
     }
 
+    protected static boolean isGenericDescriptor(DescriptorInfo desc) {
+        return desc.isDataDescriptor() && !desc.isAccessorDescriptor();
+    }
+
     protected static Scriptable ensureScriptable(Object arg) {
         if (!(arg instanceof Scriptable))
             throw ScriptRuntime.typeErrorById("msg.arg.not.object", ScriptRuntime.typeof(arg));
@@ -3085,7 +3205,7 @@ private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundE
         }
     }
 
-    protected ScriptableObject getOwnPropertyDescriptor(Context cx, Object id) {
+    protected DescriptorInfo getOwnPropertyDescriptor(Context cx, Object id) {
         Slot slot = querySlot(cx, id);
         if (slot == null) return null;
         return slot.getPropertyDescriptor(cx, this);
diff --git a/rhino/src/main/java/org/mozilla/javascript/Slot.java b/rhino/src/main/java/org/mozilla/javascript/Slot.java
index a065b96123..f0c89631c3 100644
--- a/rhino/src/main/java/org/mozilla/javascript/Slot.java
+++ b/rhino/src/main/java/org/mozilla/javascript/Slot.java
@@ -94,8 +94,8 @@ void setAttributes(int value) {
         attributes = (short) value;
     }
 
-    ScriptableObject getPropertyDescriptor(Context cx, Scriptable scope) {
-        return ScriptableObject.buildDataDescriptor(scope, value, attributes);
+    ScriptableObject.DescriptorInfo getPropertyDescriptor(Context cx, Scriptable scope) {
+        return ScriptableObject.buildDataDescriptor(value, attributes);
     }
 
     protected void throwNoSetterException(Scriptable start, Object newValue) {
diff --git a/rhino/src/main/java/org/mozilla/javascript/typedarrays/NativeTypedArrayView.java b/rhino/src/main/java/org/mozilla/javascript/typedarrays/NativeTypedArrayView.java
index dfeae01b66..9afc73fd8c 100644
--- a/rhino/src/main/java/org/mozilla/javascript/typedarrays/NativeTypedArrayView.java
+++ b/rhino/src/main/java/org/mozilla/javascript/typedarrays/NativeTypedArrayView.java
@@ -143,7 +143,7 @@ public Object[] getIds() {
 
     @Override
     protected boolean defineOwnProperty(
-            Context cx, Object id, ScriptableObject desc, boolean checkValid) {
+            Context cx, Object id, DescriptorInfo desc, boolean checkValid) {
         if (id instanceof CharSequence) {
             String name = id.toString();
             Optional<Double> num = ScriptRuntime.canonicalNumericIndexString(name);
@@ -153,21 +153,20 @@ protected boolean defineOwnProperty(
                     return false;
                 }
 
-                if (Boolean.FALSE.equals(getProperty(desc, "configurable"))) {
+                if (desc.isConfigurable(false)) {
                     return false;
                 }
-                if (Boolean.FALSE.equals(getProperty(desc, "enumerable"))) {
+                if (desc.isEnumerable(false)) {
                     return false;
                 }
-                if (isAccessorDescriptor(desc)) {
+                if (desc.isAccessorDescriptor()) {
                     return false;
                 }
-                if (Boolean.FALSE.equals(getProperty(desc, "writable"))) {
+                if (desc.isWritable(false)) {
                     return false;
                 }
-                Object value = getProperty(desc, "value");
-                if (value != NOT_FOUND) {
-                    js_set(idx, value);
+                if (desc.hasValue()) {
+                    js_set(idx, desc.value);
                 }
                 return true;
             }
diff --git a/tests/testsrc/doctests/object.defineproperty.doctest b/tests/testsrc/doctests/object.defineproperty.doctest
index 99ca62d33c..133ff0990e 100644
--- a/tests/testsrc/doctests/object.defineproperty.doctest
+++ b/tests/testsrc/doctests/object.defineproperty.doctest
@@ -130,7 +130,7 @@ js> var obj = define(obj, 'a', {get   : function() { return 4 }});
 js> obj.a
 4
 js> describe(obj, 'a').toSource()
-({enumerable:false, configurable:true, get:function() { return 4 }})
+({get:function() { return 4 }, enumerable:false, configurable:true})
 js> // can change from accessor property to data property when configurable is true
 js> var obj = define({},  'a', {get   : function() { return 2 }, configurable:true});
 js> var obj = define(obj, 'a', {value : 5});
diff --git a/tests/testsrc/test262.properties b/tests/testsrc/test262.properties
index cba22a3615..e573617d77 100644
--- a/tests/testsrc/test262.properties
+++ b/tests/testsrc/test262.properties
@@ -2023,7 +2023,7 @@ built-ins/Promise 383/639 (59.94%)
     resolve-thenable-deferred.js {unsupported: [async]}
     resolve-thenable-immed.js {unsupported: [async]}
 
-built-ins/Proxy 68/311 (21.86%)
+built-ins/Proxy 66/311 (21.22%)
     construct/arguments-realm.js
     construct/call-parameters.js
     construct/call-parameters-new-target.js
@@ -2053,7 +2053,6 @@ built-ins/Proxy 68/311 (21.86%)
     getOwnPropertyDescriptor/resultdesc-is-not-configurable-targetdesc-is-configurable.js
     getOwnPropertyDescriptor/resultdesc-is-not-configurable-targetdesc-is-undefined.js
     getOwnPropertyDescriptor/trap-is-null-target-is-proxy.js
-    get/accessor-get-is-undefined-throws.js
     get/trap-is-undefined-receiver.js
     has/call-in-prototype.js
     has/call-in-prototype-index.js
@@ -2082,7 +2081,6 @@ built-ins/Proxy 68/311 (21.86%)
     set/call-parameters-prototype.js
     set/call-parameters-prototype-dunder-proto.js
     set/call-parameters-prototype-index.js
-    set/target-property-is-accessor-not-configurable-set-is-undefined.js
     set/trap-is-missing-receiver-multiple-calls.js
     set/trap-is-missing-receiver-multiple-calls-index.js
     set/trap-is-missing-target-is-proxy.js