diff --git a/.eslintrc b/.eslintrc
index 113c77a..5634ee5 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -38,8 +38,8 @@
 				"IteratorClose",
 				"IteratorComplete",
 				"IteratorNext",
+				"IteratorStepValue",
 				"IteratorStep",
-				"IteratorValue",
 				"NormalCompletion",
 				"OrdinaryHasInstance",
 				"OrdinaryObjectCreate",
diff --git a/Iterator.prototype.drop/implementation.js b/Iterator.prototype.drop/implementation.js
index 4de2406..db186bb 100644
--- a/Iterator.prototype.drop/implementation.js
+++ b/Iterator.prototype.drop/implementation.js
@@ -10,7 +10,7 @@ var CreateIteratorFromClosure = require('../aos/CreateIteratorFromClosure');
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var IteratorClose = require('../aos/IteratorClose');
 var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
 var ToIntegerOrInfinity = require('es-abstract/2023/ToIntegerOrInfinity');
 var ToNumber = require('es-abstract/2023/ToNumber');
@@ -70,14 +70,12 @@ module.exports = function drop(limit) {
 			}
 		}
 		// while (true) { // step 6.c
-		next = IteratorStep(iterated); // step 6.c.i
-		if (!next) {
-			// return void undefined; // step 6.c.ii
-			return sentinel;
-		}
 		try {
-			var value = IteratorValue(next); // step 6.c.iii
-			return value; // step 6.c.iii
+			var value = IteratorStepValue(iterated); // step 6.b.i
+			if (iterated['[[Done]]']) {
+				return sentinel; // step 6.b.ii
+			}
+			return value;
 		} catch (e) {
 			// close iterator // step 6.c.icv
 			closeIfAbrupt(ThrowCompletion(e));
diff --git a/Iterator.prototype.every/implementation.js b/Iterator.prototype.every/implementation.js
index 36113e2..274092b 100644
--- a/Iterator.prototype.every/implementation.js
+++ b/Iterator.prototype.every/implementation.js
@@ -8,8 +8,7 @@ var Call = require('es-abstract/2023/Call');
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var IsCallable = require('es-abstract/2023/IsCallable');
 var IteratorClose = require('../aos/IteratorClose');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var NormalCompletion = require('es-abstract/2023/NormalCompletion');
 var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
 var ToBoolean = require('es-abstract/2023/ToBoolean');
@@ -35,28 +34,27 @@ module.exports = function every(predicate) {
 
 	// eslint-disable-next-line no-constant-condition
 	while (true) { // step 6
-		var next = IteratorStep(iterated); // step 6.a
-		if (!next) {
+		var value = IteratorStepValue(iterated); // step 6.a
+		if (iterated['[[Done]]']) {
 			return true; // step 6.b
 		}
-		var value = IteratorValue(next); // step 6.c
 		var result;
 		try {
-			result = Call(predicate, void undefined, [value, counter]); // step 6.d
+			result = Call(predicate, void undefined, [value, counter]); // step 6.c
 		} catch (e) {
-			// close iterator // step 6.e
+			// close iterator // step 6.d
 			IteratorClose(
 				iterated,
 				ThrowCompletion(e)
 			);
 		} finally {
-			counter += 1; // step 6.g
+			counter += 1; // step 6.f
 		}
 		if (!ToBoolean(result)) {
 			return IteratorClose(
 				iterated,
 				NormalCompletion(false)
-			); // step 6.f
+			); // step 6.e
 		}
 	}
 };
diff --git a/Iterator.prototype.filter/implementation.js b/Iterator.prototype.filter/implementation.js
index e5179fb..ee58fe9 100644
--- a/Iterator.prototype.filter/implementation.js
+++ b/Iterator.prototype.filter/implementation.js
@@ -10,8 +10,7 @@ var CreateIteratorFromClosure = require('../aos/CreateIteratorFromClosure');
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var IsCallable = require('es-abstract/2023/IsCallable');
 var IteratorClose = require('../aos/IteratorClose');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
 var ToBoolean = require('es-abstract/2023/ToBoolean');
 var Type = require('es-abstract/2023/Type');
@@ -51,12 +50,11 @@ module.exports = function filter(predicate) {
 	var closure = function () {
 		// eslint-disable-next-line no-constant-condition
 		while (true) { // step 6.b
-			var next = IteratorStep(iterated); // step 6.b.i
-			if (!next) {
-				// return void undefined; // step 6.b.ii
-				return sentinel;
+			var value = IteratorStepValue(iterated); // step 6.b.i
+			if (iterated['[[Done]]']) {
+				return sentinel; // step 6.b.ii
 			}
-			var value = IteratorValue(next); // step 6.b.iii
+
 			var selected;
 			try {
 				selected = Call(predicate, void undefined, [value, counter]); // step 6.b.iv
diff --git a/Iterator.prototype.find/implementation.js b/Iterator.prototype.find/implementation.js
index 936de8a..10abc2c 100644
--- a/Iterator.prototype.find/implementation.js
+++ b/Iterator.prototype.find/implementation.js
@@ -8,8 +8,7 @@ var Call = require('es-abstract/2023/Call');
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var IsCallable = require('es-abstract/2023/IsCallable');
 var IteratorClose = require('../aos/IteratorClose');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var NormalCompletion = require('es-abstract/2023/NormalCompletion');
 var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
 var ToBoolean = require('es-abstract/2023/ToBoolean');
@@ -36,28 +35,27 @@ module.exports = function find(predicate) {
 
 	// eslint-disable-next-line no-constant-condition
 	while (true) { // step 6
-		var next = IteratorStep(iterated); // step 6.a
-		if (!next) {
+		var value = IteratorStepValue(iterated); // step 6.a
+		if (iterated['[[Done]]']) {
 			return void undefined; // step 6.b
 		}
-		var value = IteratorValue(next); // step 6.c
 		var result;
 		try {
-			result = Call(predicate, void undefined, [value, counter]); // step 6.d
+			result = Call(predicate, void undefined, [value, counter]); // step 6.c
 		} catch (e) {
-			// close iterator // step 6.e
+			// close iterator // step 6.d
 			IteratorClose(
 				iterated,
 				ThrowCompletion(e)
 			);
 		} finally {
-			counter += 1; // step 6.g
+			counter += 1; // step 6.f
 		}
 		if (ToBoolean(result)) {
 			return IteratorClose(
 				iterated,
 				NormalCompletion(value)
-			); // step 6.f
+			); // step 6.e
 		}
 	}
 };
diff --git a/Iterator.prototype.flatMap/implementation.js b/Iterator.prototype.flatMap/implementation.js
index a680963..57b4eb1 100644
--- a/Iterator.prototype.flatMap/implementation.js
+++ b/Iterator.prototype.flatMap/implementation.js
@@ -11,8 +11,7 @@ var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var GetIteratorFlattenable = require('../aos/GetIteratorFlattenable');
 var IsCallable = require('es-abstract/2023/IsCallable');
 var IteratorClose = require('../aos/IteratorClose');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
 var Type = require('es-abstract/2023/Type');
 
@@ -65,14 +64,13 @@ module.exports = function flatMap(mapper) {
 	var closure = function () {
 		// while (true) { // step 5.b
 		if (innerIterator === sentinel) {
-			var next = IteratorStep(iterated); // step 5.b.i
-			if (!next) {
+			var value = IteratorStepValue(iterated); // step 5.b.i
+			if (iterated['[[Done]]']) {
 				innerAlive = false;
 				innerIterator = sentinel;
 				// return void undefined; // step 5.b.ii
 				return sentinel;
 			}
-			var value = IteratorValue(next); // step 5.b.iii
 		}
 
 		if (innerIterator === sentinel) {
@@ -91,27 +89,20 @@ module.exports = function flatMap(mapper) {
 		}
 		// while (innerAlive) { // step 5.b.ix
 		if (innerAlive) {
-			var innerNext;
-			try {
-				innerNext = IteratorStep(innerIterator); // step 5.b.ix.1
-			} catch (e) {
-				innerIterator = sentinel;
-				closeIfAbrupt(ThrowCompletion(e)); // step 5.b.ix.2
-			}
-			if (!innerNext) {
-				innerAlive = false; // step 5.b.ix.3.a
-				innerIterator = sentinel;
-				return closure();
-			}
 			// step 5.b.ix.4
 			var innerValue;
 			try {
-				innerValue = IteratorValue(innerNext); // step 5.b.ix.4.a
+				innerValue = IteratorStepValue(innerIterator); // step 5.b.ix.4.a
 			} catch (e) {
 				innerAlive = false;
 				innerIterator = sentinel;
 				closeIfAbrupt(ThrowCompletion(e)); // step 5.b.ix.4.b
 			}
+			if (innerIterator['[[Done]]']) {
+				innerAlive = false;
+				innerIterator = sentinel;
+				return closure();
+			}
 			return innerValue; // step 5.b.ix.4.c
 		}
 		// }
diff --git a/Iterator.prototype.forEach/implementation.js b/Iterator.prototype.forEach/implementation.js
index cfb9fb6..94e914f 100644
--- a/Iterator.prototype.forEach/implementation.js
+++ b/Iterator.prototype.forEach/implementation.js
@@ -8,8 +8,7 @@ var Call = require('es-abstract/2023/Call');
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var IsCallable = require('es-abstract/2023/IsCallable');
 var IteratorClose = require('../aos/IteratorClose');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
 var Type = require('es-abstract/2023/Type');
 
@@ -33,21 +32,20 @@ module.exports = function forEach(fn) {
 
 	// eslint-disable-next-line no-constant-condition
 	while (true) { // step 6
-		var next = IteratorStep(iterated); // step 6.a
-		if (!next) {
+		var value = IteratorStepValue(iterated); // step 6.a
+		if (iterated['[[Done]]']) {
 			return void undefined; // step 6.b
 		}
-		var value = IteratorValue(next); // step 6.c
 		try {
-			Call(fn, void undefined, [value, counter]); // step 6.d
+			Call(fn, void undefined, [value, counter]); // step 6.c
 		} catch (e) {
 			IteratorClose(
 				iterated,
 				ThrowCompletion(e)
-			); // steps 6.e
+			); // steps 6.d
 			throw e;
 		} finally {
-			counter += 1; // step 6.f
+			counter += 1; // step 6.e
 		}
 	}
 };
diff --git a/Iterator.prototype.map/implementation.js b/Iterator.prototype.map/implementation.js
index 4c4e26a..be69634 100644
--- a/Iterator.prototype.map/implementation.js
+++ b/Iterator.prototype.map/implementation.js
@@ -10,8 +10,7 @@ var CreateIteratorFromClosure = require('../aos/CreateIteratorFromClosure');
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var IsCallable = require('es-abstract/2023/IsCallable');
 var IteratorClose = require('../aos/IteratorClose');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
 var Type = require('es-abstract/2023/Type');
 
@@ -49,16 +48,14 @@ module.exports = function map(mapper) {
 	var counter = 0; // step 6.a
 	var closure = function () {
 		// while (true) { // step 6.b
-		var next = IteratorStep(iterated); // step 6.b.i
-
-		if (!next) {
-			// return void undefined; // step 6.b.ii
-			return sentinel;
+		var value = IteratorStepValue(iterated); // step 6.b.i
+		if (iterated['[[Done]]']) {
+			return sentinel; // step 6.b.ii
 		}
-		var value = IteratorValue(next); // step 6.b.iii
+
 		var mapped;
 		try {
-			mapped = Call(mapper, void undefined, [value, counter]); // step 6.b.iv
+			mapped = Call(mapper, void undefined, [value, counter]); // step 6.b.iii
 			// yield mapped // step 6.b.vi
 			return mapped;
 		} catch (e) {
diff --git a/Iterator.prototype.reduce/implementation.js b/Iterator.prototype.reduce/implementation.js
index 643cf30..bd70861 100644
--- a/Iterator.prototype.reduce/implementation.js
+++ b/Iterator.prototype.reduce/implementation.js
@@ -8,8 +8,7 @@ var Call = require('es-abstract/2023/Call');
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var IsCallable = require('es-abstract/2023/IsCallable');
 var IteratorClose = require('../aos/IteratorClose');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
 var Type = require('es-abstract/2023/Type');
 
@@ -31,13 +30,11 @@ module.exports = function reduce(reducer) {
 
 	var accumulator;
 	var counter;
-	var next;
 	if (arguments.length < 2) { // step 6
-		next = IteratorStep(iterated); // step 6.a
-		if (!next) {
-			throw new $TypeError('Reduce of empty iterator with no initial value'); // step 6.b
+		accumulator = IteratorStepValue(iterated); // step 6.a
+		if (iterated['[[Done]]']) {
+			throw new $TypeError('Reduce of empty iterator with no initial value');
 		}
-		accumulator = IteratorValue(next); // step 6.c
 		counter = 1;
 	} else { // step 7
 		accumulator = arguments[1]; // step 7.a
@@ -46,11 +43,10 @@ module.exports = function reduce(reducer) {
 
 	// eslint-disable-next-line no-constant-condition
 	while (true) { // step 8
-		next = IteratorStep(iterated); // step 8.a
-		if (!next) {
+		var value = IteratorStepValue(iterated); // step 8.a
+		if (iterated['[[Done]]']) {
 			return accumulator; // step 8.b
 		}
-		var value = IteratorValue(next); // step 8.c
 		try {
 			var result = Call(reducer, void undefined, [accumulator, value, counter]); // step 8.d
 			accumulator = result; // step 8.f
diff --git a/Iterator.prototype.some/implementation.js b/Iterator.prototype.some/implementation.js
index 640830d..215e121 100644
--- a/Iterator.prototype.some/implementation.js
+++ b/Iterator.prototype.some/implementation.js
@@ -8,8 +8,7 @@ var Call = require('es-abstract/2023/Call');
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var IsCallable = require('es-abstract/2023/IsCallable');
 var IteratorClose = require('../aos/IteratorClose');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var NormalCompletion = require('es-abstract/2023/NormalCompletion');
 var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
 var ToBoolean = require('es-abstract/2023/ToBoolean');
@@ -35,28 +34,27 @@ module.exports = function some(predicate) {
 
 	// eslint-disable-next-line no-constant-condition
 	while (true) { // step 6
-		var next = IteratorStep(iterated); // step 6.a
-		if (!next) {
+		var value = IteratorStepValue(iterated); // step 6.a
+		if (iterated['[[Done]]']) {
 			return false; // step 6.b
 		}
-		var value = IteratorValue(next); // step 6.c
 		var result;
 		try {
-			result = Call(predicate, void undefined, [value, counter]); // step 6.d
+			result = Call(predicate, void undefined, [value, counter]); // step 6.c
 		} catch (e) {
-			// close iterator // step 6.e
+			// close iterator // step 6.d
 			IteratorClose(
 				iterated,
 				ThrowCompletion(e)
 			);
 		} finally {
-			counter += 1; // step 6.g
+			counter += 1; // step 6.f
 		}
 		if (ToBoolean(result)) {
 			return IteratorClose(
 				iterated,
 				NormalCompletion(true)
-			); // step 6.f
+			); // step 6.e
 		}
 	}
 };
diff --git a/Iterator.prototype.take/implementation.js b/Iterator.prototype.take/implementation.js
index 77f131f..10fa7af 100644
--- a/Iterator.prototype.take/implementation.js
+++ b/Iterator.prototype.take/implementation.js
@@ -9,8 +9,7 @@ var CompletionRecord = require('es-abstract/2023/CompletionRecord');
 var CreateIteratorFromClosure = require('../aos/CreateIteratorFromClosure');
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
 var IteratorClose = require('../aos/IteratorClose');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var NormalCompletion = require('es-abstract/2023/NormalCompletion');
 var ToIntegerOrInfinity = require('es-abstract/2023/ToIntegerOrInfinity');
 var ToNumber = require('es-abstract/2023/ToNumber');
@@ -68,13 +67,11 @@ module.exports = function take(limit) {
 			remaining -= 1; // step 9.b.ii.1
 		}
 
-		var next = IteratorStep(iterated); // step 9.b.iii
-		if (!next) {
-			// return void undefined; // step 9.b.iv
-			return sentinel;
+		var value = IteratorStepValue(iterated); // step 6.b.i
+		if (iterated['[[Done]]']) {
+			return sentinel; // step 6.b.ii
 		}
 
-		var value = IteratorValue(next); // step 9.b.iii
 		return value; // step 9.b.iv
 		// }
 	};
diff --git a/Iterator.prototype.toArray/implementation.js b/Iterator.prototype.toArray/implementation.js
index f63f8f1..25cb294 100644
--- a/Iterator.prototype.toArray/implementation.js
+++ b/Iterator.prototype.toArray/implementation.js
@@ -5,8 +5,7 @@ var GetIntrinsic = require('get-intrinsic');
 var $TypeError = GetIntrinsic('%TypeError%');
 
 var GetIteratorDirect = require('../aos/GetIteratorDirect');
-var IteratorStep = require('es-abstract/2023/IteratorStep');
-var IteratorValue = require('es-abstract/2023/IteratorValue');
+var IteratorStepValue = require('../aos/IteratorStepValue');
 var Type = require('es-abstract/2023/Type');
 
 var callBound = require('call-bind/callBound');
@@ -30,11 +29,10 @@ module.exports = function toArray() {
 
 	// eslint-disable-next-line no-constant-condition
 	while (true) { // step 5
-		var next = IteratorStep(iterated); // step 5.a
-		if (!next) {
+		var value = IteratorStepValue(iterated); // step 5.a
+		if (iterated['[[Done]]']) {
 			return items; // step 5.b
 		}
-		var value = IteratorValue(next); // step 5.c
 		$push(items, value); // step 5.d
 	}
 };
diff --git a/aos/CreateIteratorFromClosure.js b/aos/CreateIteratorFromClosure.js
index a2f5cd2..9779ab1 100644
--- a/aos/CreateIteratorFromClosure.js
+++ b/aos/CreateIteratorFromClosure.js
@@ -8,7 +8,6 @@ var GeneratorStart = require('./GeneratorStart');
 var IsArray = require('es-abstract/2023/IsArray');
 var IsCallable = require('es-abstract/2023/IsCallable');
 var OrdinaryObjectCreate = require('es-abstract/2023/OrdinaryObjectCreate');
-var Type = require('es-abstract/2023/Type');
 
 var every = require('es-abstract/helpers/every');
 
@@ -17,14 +16,14 @@ var SLOT = require('internal-slot');
 var safeConcat = require('safe-array-concat');
 
 var isString = function isString(slot) {
-	return Type(slot) === 'String';
+	return typeof slot === 'string';
 };
 
 module.exports = function CreateIteratorFromClosure(closure, generatorBrand, proto) {
 	if (!IsCallable(closure)) {
 		throw new $TypeError('`closure` must be a function');
 	}
-	if (Type(generatorBrand) !== 'String') {
+	if (typeof generatorBrand !== 'string') {
 		throw new $TypeError('`generatorBrand` must be a string');
 	}
 	var extraSlots = arguments.length > 3 ? arguments[3] : [];
diff --git a/aos/IteratorStepValue.js b/aos/IteratorStepValue.js
new file mode 100644
index 0000000..5b3ef4c
--- /dev/null
+++ b/aos/IteratorStepValue.js
@@ -0,0 +1,47 @@
+'use strict';
+
+var Get = require('es-abstract/2023/Get');
+var IteratorComplete = require('es-abstract/2023/IteratorComplete');
+var IteratorNext = require('es-abstract/2023/IteratorNext');
+var Type = require('es-abstract/2023/Type');
+
+var assertRecord = require('es-abstract/helpers/assertRecord');
+
+// https://262.ecma-international.org/15.0/#sec-iteratorstepvalue
+
+module.exports = function IteratorStepValue(iteratorRecord) {
+	assertRecord(Type, 'Iterator Record', 'iteratorRecord', iteratorRecord);
+	/* eslint no-param-reassign: 0 */
+
+	var result;
+	try {
+		result = IteratorNext(iteratorRecord); // step 1
+	} catch (e) { // step 2
+		iteratorRecord['[[Done]]'] = true; // step 2.a
+		throw e; // step 2.b
+	}
+
+	var done;
+	try {
+		done = IteratorComplete(result); // step 4
+	} catch (e) { // step 5
+		iteratorRecord['[[Done]]'] = true; // step 5.a
+		throw e; // step 5.b
+	}
+
+	if (done) { // step 7
+		iteratorRecord['[[Done]]'] = true; // step 7.a
+		return 'DONE'; // step 7.b
+	}
+
+	var value;
+	try {
+		value = Get(result, 'value'); // step 8
+	} catch (e) { // step 9
+		iteratorRecord['[[Done]]'] = true; // step 9.a
+		throw e; // step 10
+	}
+
+	return value; // step 10
+};
+