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lib: add Iterator global to primordials, improve iteration object coverage in frozen intrinsics #63698

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04ad7a7
lib: add Iterator global to primordials
Renegade334 Jun 1, 2026
17d237b
lib: improve control abstraction coverage in frozen intrinsics
Renegade334 Jun 1, 2026
27ea243
fixup! lib: improve control abstraction coverage in frozen intrinsics
Renegade334 Jun 11, 2026
3296e1f
fixup! lib: improve control abstraction coverage in frozen intrinsics
Renegade334 Jun 11, 2026
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5 changes: 1 addition & 4 deletions lib/eslint.config_partial.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -164,10 +164,6 @@ export default [
name: 'Intl',
message: 'Use `const { Intl } = globalThis;` instead of the global.',
},
{
name: 'Iterator',
message: 'Use `const { Iterator } = globalThis;` instead of the global.',
},
{
name: 'MessageChannel',
message: "Use `const { MessageChannel } = require('internal/worker/io');` instead of the global.",
Expand Down Expand Up @@ -464,6 +460,7 @@ export default [
{ name: 'Int16Array' },
{ name: 'Int32Array' },
{ name: 'Int8Array' },
{ name: 'Iterator' },
{
name: 'isFinite',
into: 'Number',
Expand Down
63 changes: 37 additions & 26 deletions lib/internal/freeze_intrinsics.js
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,9 @@ const {
ArrayPrototype,
ArrayPrototypeForEach,
ArrayPrototypePush,
AsyncFunctionPrototype,
AsyncGeneratorFunctionPrototype,
AsyncGeneratorFunctionPrototypePrototype,
AsyncIteratorPrototype,
Atomics,
BigInt,
Expand All @@ -57,14 +60,19 @@ const {
Float64ArrayPrototype,
Function,
FunctionPrototype,
GeneratorFunctionPrototype,
GeneratorFunctionPrototypePrototype,
Int16Array,
Int16ArrayPrototype,
Int32Array,
Int32ArrayPrototype,
Int8Array,
Int8ArrayPrototype,
Iterator,
IteratorHelperPrototype,
IteratorPrototype,
Map,
MapIteratorPrototype,
MapPrototype,
Number,
NumberPrototype,
Expand All @@ -88,15 +96,15 @@ const {
ReflectOwnKeys,
RegExp,
RegExpPrototype,
RegExpStringIteratorPrototype,
SafeSet,
Set,
SetIteratorPrototype,
SetPrototype,
String,
StringIteratorPrototype,
StringPrototype,
Symbol,
SymbolIterator,
SymbolMatchAll,
SymbolPrototype,
SyntaxError,
SyntaxErrorPrototype,
Expand All @@ -120,6 +128,7 @@ const {
WeakRefPrototype,
WeakSet,
WeakSetPrototype,
WrapForValidIteratorPrototype,
decodeURI,
decodeURIComponent,
encodeURI,
Expand Down Expand Up @@ -173,8 +182,7 @@ module.exports = function() {
StringPrototype, // 22.1
StringIteratorPrototype, // 22.1.5
RegExpPrototype, // 22.2
// 22.2.7 RegExpStringIteratorPrototype
ObjectGetPrototypeOf(/e/[SymbolMatchAll]()),
RegExpStringIteratorPrototype, // 22.2.9

// 23 Indexed Collections
ArrayPrototype, // 23.1
Expand All @@ -195,11 +203,9 @@ module.exports = function() {

// 24 Keyed Collections
MapPrototype, // 24.1
// 24.1.5 MapIteratorPrototype
ObjectGetPrototypeOf(new Map()[SymbolIterator]()),
MapIteratorPrototype, // 24.1.5
SetPrototype, // 24.2
// 24.2.5 SetIteratorPrototype
ObjectGetPrototypeOf(new Set()[SymbolIterator]()),
SetIteratorPrototype, // 24.2.6
WeakMapPrototype, // 24.3
WeakSetPrototype, // 24.4

Expand All @@ -212,10 +218,18 @@ module.exports = function() {
FinalizationRegistryPrototype, // 26.2

// 27 Control Abstraction Objects
// 27.1 Iteration
IteratorPrototype, // 27.1.2 IteratorPrototype
AsyncIteratorPrototype, // 27.1.3 AsyncIteratorPrototype
IteratorHelperPrototype, // 27.1.2
IteratorPrototype, // 27.1.3
WrapForValidIteratorPrototype, // 27.1.3.2.2.1
AsyncIteratorPrototype, // 27.1.4
PromisePrototype, // 27.2
GeneratorFunctionPrototype, // 27.3
AsyncGeneratorFunctionPrototype, // 27.4
// 27.5 GeneratorPrototype
GeneratorFunctionPrototypePrototype,
// 27.6 AsyncGeneratorPrototype
AsyncGeneratorFunctionPrototypePrototype,
AsyncFunctionPrototype, // 27.7

// Other APIs / Web Compatibility
Console.prototype,
Expand Down Expand Up @@ -268,8 +282,7 @@ module.exports = function() {
String, // 22.1
StringIteratorPrototype, // 22.1.5
RegExp, // 22.2
// 22.2.7 RegExpStringIteratorPrototype
ObjectGetPrototypeOf(/e/[SymbolMatchAll]()),
RegExpStringIteratorPrototype, // 22.2.9

// 23 Indexed Collections
Array, // 23.1
Expand All @@ -290,11 +303,9 @@ module.exports = function() {

// 24 Keyed Collections
Map, // 24.1
// 24.1.5 MapIteratorPrototype
ObjectGetPrototypeOf(new Map()[SymbolIterator]()),
MapIteratorPrototype, // 24.1.5
Set, // 24.2
// 24.2.5 SetIteratorPrototype
ObjectGetPrototypeOf(new Set()[SymbolIterator]()),
SetIteratorPrototype, // 24.2.6
WeakMap, // 24.3
WeakSet, // 24.4

Expand All @@ -310,19 +321,19 @@ module.exports = function() {
FinalizationRegistry, // 26.2

// 27 Control Abstraction Objects
// 27.1 Iteration
ObjectGetPrototypeOf(ArrayIteratorPrototype), // 27.1.2 IteratorPrototype
// 27.1.3 AsyncIteratorPrototype
ObjectGetPrototypeOf(ObjectGetPrototypeOf(ObjectGetPrototypeOf(
(async function*() {})(),
))),
IteratorHelperPrototype, // 27.1.2
Iterator, // 27.1.3
WrapForValidIteratorPrototype, // 27.1.3.2.2.1
ArrayIteratorPrototype, // 27.1.4
Promise, // 27.2
// 27.3 GeneratorFunction
ObjectGetPrototypeOf(function* () {}),
// 27.5 Generator
GeneratorFunctionPrototype,
// 27.4 AsyncGeneratorFunction
ObjectGetPrototypeOf(async function* () {}),
// 27.6 AsyncGenerator
AsyncGeneratorFunctionPrototype,
// 27.7 AsyncFunction
ObjectGetPrototypeOf(async function() {}),
AsyncFunctionPrototype,

// 28 Reflection
// eslint-disable-next-line node-core/prefer-primordials
Expand Down
88 changes: 63 additions & 25 deletions lib/internal/per_context/primordials.js
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Original file line number Diff line number Diff line change
Expand Up @@ -202,6 +202,7 @@ function copyPrototype(src, dest, prefix) {
'Int16Array',
'Int32Array',
'Int8Array',
'Iterator',
'Map',
'Number',
'Object',
Expand Down Expand Up @@ -230,10 +231,10 @@ function copyPrototype(src, dest, prefix) {
});


// Create copies of intrinsic objects that require a valid `this` to call
// static methods.
// Refs: https://www.ecma-international.org/ecma-262/#sec-promise.all
// Create copies of intrinsic objects whose static methods require the
// constructor to be passed as the receiver.
[
// Refs: https://tc39.es/ecma-262/#sec-promise.all
'Promise',
].forEach((name) => {
// eslint-disable-next-line no-restricted-globals
Expand All @@ -244,25 +245,68 @@ function copyPrototype(src, dest, prefix) {
});

// Create copies of abstract intrinsic objects that are not directly exposed
// on the global object.
// Refs: https://tc39.es/ecma262/#sec-%typedarray%-intrinsic-object
// on the global object, and whose static methods require a valid subclass
// constructor to be passed as the receiver.
[
// Refs: https://tc39.es/ecma262/#sec-%typedarray%-intrinsic-object
{ name: 'TypedArray', original: Reflect.getPrototypeOf(Uint8Array) },
{ name: 'ArrayIterator', original: {
prototype: Reflect.getPrototypeOf(Array.prototype[Symbol.iterator]()),
} },
{ name: 'StringIterator', original: {
prototype: Reflect.getPrototypeOf(String.prototype[Symbol.iterator]()),
} },
Comment thread
ljharb marked this conversation as resolved.
].forEach(({ name, original }) => {
primordials[name] = original;
// The static %TypedArray% methods require a valid `this`, but can't be bound,
// as they need a subclass constructor as the receiver:
copyPrototype(original, primordials, name);
copyPrototype(original.prototype, primordials, `${name}Prototype`);
});

primordials.IteratorPrototype = Reflect.getPrototypeOf(primordials.ArrayIteratorPrototype);
// Create copies of abstract intrinsic prototypes that are not directly exposed
// on the global object and which do not have corresponding constructors.
[
{
name: 'ArrayIteratorPrototype',
original: Reflect.getPrototypeOf(Array.prototype[Symbol.iterator]()),
},
{
name: 'AsyncFunctionPrototype',
original: Reflect.getPrototypeOf(async function() {}),
},
{
name: 'AsyncGeneratorFunctionPrototype',
original: Reflect.getPrototypeOf(async function*() {}),
},
{
name: 'AsyncIteratorPrototype',
original: Reflect.getPrototypeOf(Reflect.getPrototypeOf(async function*() {}).prototype),
},
{
name: 'GeneratorFunctionPrototype',
original: Reflect.getPrototypeOf(function*() {}),
},
{
name: 'IteratorHelperPrototype',
original: Reflect.getPrototypeOf(primordials.IteratorPrototypeDrop({ __proto__: null }, null)),
},
{
name: 'MapIteratorPrototype',
original: Reflect.getPrototypeOf(new primordials.Map()[Symbol.iterator]()),
},
{
name: 'RegExpStringIteratorPrototype',
original: Reflect.getPrototypeOf(primordials.RegExp.prototype[Symbol.matchAll]()),
},
{
name: 'SetIteratorPrototype',
original: Reflect.getPrototypeOf(new primordials.Set()[Symbol.iterator]()),
},
{
name: 'StringIteratorPrototype',
original: Reflect.getPrototypeOf(String.prototype[Symbol.iterator]()),
},
{
name: 'WrapForValidIteratorPrototype',
original: Reflect.getPrototypeOf(primordials.IteratorFrom({ __proto__: null })),
},
].forEach(({ name, original }) => {
Comment thread
aduh95 marked this conversation as resolved.
primordials[name] = original;
copyPrototype(original, primordials, name);
});

/* eslint-enable node-core/prefer-primordials */

Expand Down Expand Up @@ -366,21 +410,18 @@ const copyProps = (src, dest) => {
/**
* @type {typeof primordials.makeSafe}
*/
const makeSafe = (unsafe, safe) => {
if (SymbolIterator in unsafe.prototype) {
const makeSafe = (unsafe, safe, next) => {
if (next) {
const dummy = new unsafe();
let next; // We can reuse the same `next` method.

ArrayPrototypeForEach(ReflectOwnKeys(unsafe.prototype), (key) => {
if (!ReflectGetOwnPropertyDescriptor(safe.prototype, key)) {
const desc = ReflectGetOwnPropertyDescriptor(unsafe.prototype, key);
if (
typeof desc.value === 'function' &&
desc.value.length === 0 &&
SymbolIterator in (FunctionPrototypeCall(desc.value, dummy) ?? {})
FunctionPrototypeCall(desc.value, dummy)?.next === next
) {
const createIterator = uncurryThis(desc.value);
next ??= uncurryThis(createIterator(dummy).next);
const SafeIterator = createSafeIterator(createIterator, next);
desc.value = function() {
return new SafeIterator(this);
Expand All @@ -406,6 +447,7 @@ primordials.makeSafe = makeSafe;
primordials.SafeMap = makeSafe(
Map,
class SafeMap extends Map {},
primordials.MapIteratorPrototypeNext,
);
primordials.SafeWeakMap = makeSafe(
WeakMap,
Expand All @@ -415,6 +457,7 @@ primordials.SafeWeakMap = makeSafe(
primordials.SafeSet = makeSafe(
Set,
class SafeSet extends Set {},
primordials.SetIteratorPrototypeNext,
);
primordials.SafeWeakSet = makeSafe(
WeakSet,
Expand Down Expand Up @@ -453,11 +496,6 @@ primordials.SafePromisePrototypeFinally = (thisPromise, onFinally) =>
.then(a, b),
);

primordials.AsyncIteratorPrototype =
primordials.ReflectGetPrototypeOf(
primordials.ReflectGetPrototypeOf(
async function* () {}).prototype);

const arrayToSafePromiseIterable = (promises, mapFn) =>
new primordials.SafeArrayIterator(
ArrayPrototypeMap(
Expand Down
34 changes: 32 additions & 2 deletions typings/primordials.d.ts
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Expand Up @@ -40,7 +40,7 @@ type TypedArrayContentType<T extends TypedArrayConstructor> = InstanceType<T>[nu
*/
declare namespace primordials {
export function uncurryThis<T extends (...args: unknown[]) => unknown>(fn: T): UncurryThis<T>;
export function makeSafe<T extends NewableFunction>(unsafe: NewableFunction, safe: T): T;
export function makeSafe<T extends NewableFunction>(unsafe: NewableFunction, safe: T, next?: Function): T;

export import decodeURI = globalThis.decodeURI;
export import decodeURIComponent = globalThis.decodeURIComponent;
Expand Down Expand Up @@ -168,7 +168,6 @@ declare namespace primordials {
export const ArrayBufferPrototypeSlice: UncurryThis<typeof ArrayBuffer.prototype.slice>
export const ArrayBufferPrototypeTransfer: UncurryThis<typeof ArrayBuffer.prototype.transfer>
export const ArrayBufferPrototypeGetByteLength: UncurryGetter<typeof ArrayBuffer.prototype , "byteLength">;
export const AsyncIteratorPrototype: AsyncIterable<any>;
export import BigInt = globalThis.BigInt;
export const BigIntPrototype: typeof BigInt.prototype
export const BigIntAsUintN: typeof BigInt.asUintN
Expand Down Expand Up @@ -545,6 +544,37 @@ declare namespace primordials {
export const PromisePrototypeFinally: UncurryThis<typeof Promise.prototype.finally>
export const PromiseWithResolvers: typeof Promise.withResolvers
export import Proxy = globalThis.Proxy
export import Iterator = globalThis.Iterator
export const IteratorFrom: typeof Iterator.from
export const IteratorPrototype: typeof Iterator.prototype
export const IteratorPrototypeDrop: UncurryThis<typeof Iterator.prototype.drop>
export const IteratorPrototypeEvery: UncurryThis<typeof Iterator.prototype.every>
export const IteratorPrototypeFilter: UncurryThis<typeof Iterator.prototype.filter>
export const IteratorPrototypeFind: UncurryThis<typeof Iterator.prototype.find>
export const IteratorPrototypeFlatMap: UncurryThis<typeof Iterator.prototype.flatMap>
export const IteratorPrototypeForEach: UncurryThis<typeof Iterator.prototype.forEach>
export const IteratorPrototypeMap: UncurryThis<typeof Iterator.prototype.map>
export const IteratorPrototypeReduce: UncurryThis<typeof Iterator.prototype.reduce>
export const IteratorPrototypeSome: UncurryThis<typeof Iterator.prototype.some>
export const IteratorPrototypeTake: UncurryThis<typeof Iterator.prototype.take>
export const IteratorPrototypeToArray: UncurryThis<typeof Iterator.prototype.toArray>
export const IteratorPrototypeSymbolIterator: UncurryMethod<typeof Iterator.prototype, typeof Symbol.iterator>
export const ArrayIteratorPrototype: ReturnType<typeof Array.prototype[typeof Symbol.iterator]>
export const ArrayIteratorPrototypeNext: UncurryThis<typeof ArrayIteratorPrototype.next>
export const AsyncFunctionPrototype: Function
export const AsyncGeneratorFunctionPrototype: Function
export const AsyncIteratorPrototype: AsyncIterable<any>
export const GeneratorFunctionPrototype: Function
export const IteratorHelperPrototype: ReturnType<typeof Iterator.prototype.drop>
export const MapIteratorPrototype: ReturnType<typeof Map.prototype[typeof Symbol.iterator]>
export const MapIteratorPrototypeNext: UncurryThis<typeof MapIteratorPrototype.next>
export const RegExpStringIteratorPrototype: ReturnType<typeof RegExp.prototype[typeof Symbol.matchAll]>
export const RegExpStringIteratorPrototypeNext: UncurryThis<typeof RegExpStringIteratorPrototype.next>
export const SetIteratorPrototype: ReturnType<typeof Set.prototype[typeof Symbol.iterator]>
export const SetIteratorPrototypeNext: UncurryThis<typeof SetIteratorPrototype.next>
export const StringIteratorPrototype: ReturnType<typeof String.prototype[typeof Symbol.iterator]>
export const StringIteratorPrototypeNext: UncurryThis<typeof StringIteratorPrototype.next>
export const WrapForValidIteratorPrototype: ReturnType<typeof Iterator.from>
import _globalThis = globalThis
export { _globalThis as globalThis }
}
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