352 lines
10 KiB
JavaScript
352 lines
10 KiB
JavaScript
"use strict";
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// Returns "Type(value) is Object" in ES terminology.
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function isObject(value) {
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return (typeof value === "object" && value !== null) || typeof value === "function";
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}
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const call = Function.call.bind(Function.call);
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// Like `Object.assign`, but using `[[GetOwnProperty]]` and `[[DefineOwnProperty]]`
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// instead of `[[Get]]` and `[[Set]]` and only allowing objects
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function define(target, source) {
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for (const key of Reflect.ownKeys(source)) {
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const descriptor = Reflect.getOwnPropertyDescriptor(source, key);
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if (descriptor && !Reflect.defineProperty(target, key, descriptor)) {
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throw new TypeError(`Cannot redefine property: ${String(key)}`);
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}
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}
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}
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function newObjectInRealm(globalObject, object) {
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const ctorRegistry = initCtorRegistry(globalObject);
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return Object.defineProperties(
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Object.create(ctorRegistry["%Object.prototype%"]),
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Object.getOwnPropertyDescriptors(object)
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);
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}
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const wrapperSymbol = Symbol("wrapper");
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const implSymbol = Symbol("impl");
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const sameObjectCaches = Symbol("SameObject caches");
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const ctorRegistrySymbol = Symbol.for("[webidl2js] constructor registry");
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const AsyncIteratorPrototype = Object.getPrototypeOf(Object.getPrototypeOf(async function* () {}).prototype);
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function initCtorRegistry(globalObject) {
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if (Object.hasOwn(globalObject, ctorRegistrySymbol)) {
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return globalObject[ctorRegistrySymbol];
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}
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const ctorRegistry = Object.create(null);
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// In addition to registering all the WebIDL2JS-generated types in the constructor registry,
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// we also register a few intrinsics that we make use of in generated code, since they are not
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// easy to grab from the globalObject variable.
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ctorRegistry["%Object.prototype%"] = globalObject.Object.prototype;
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ctorRegistry["%IteratorPrototype%"] = Object.getPrototypeOf(
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Object.getPrototypeOf(new globalObject.Array()[Symbol.iterator]())
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);
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try {
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ctorRegistry["%AsyncIteratorPrototype%"] = Object.getPrototypeOf(
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Object.getPrototypeOf(
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globalObject.eval("(async function* () {})").prototype
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)
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);
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} catch {
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ctorRegistry["%AsyncIteratorPrototype%"] = AsyncIteratorPrototype;
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}
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globalObject[ctorRegistrySymbol] = ctorRegistry;
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return ctorRegistry;
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}
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function getSameObject(wrapper, prop, creator) {
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if (!wrapper[sameObjectCaches]) {
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wrapper[sameObjectCaches] = Object.create(null);
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}
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if (prop in wrapper[sameObjectCaches]) {
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return wrapper[sameObjectCaches][prop];
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}
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wrapper[sameObjectCaches][prop] = creator();
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return wrapper[sameObjectCaches][prop];
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}
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function wrapperForImpl(impl) {
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return impl ? impl[wrapperSymbol] : null;
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}
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function implForWrapper(wrapper) {
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return wrapper ? wrapper[implSymbol] : null;
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}
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function tryWrapperForImpl(impl) {
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const wrapper = wrapperForImpl(impl);
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return wrapper ? wrapper : impl;
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}
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function tryImplForWrapper(wrapper) {
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const impl = implForWrapper(wrapper);
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return impl ? impl : wrapper;
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}
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const iterInternalSymbol = Symbol("internal");
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function isArrayIndexPropName(P) {
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if (typeof P !== "string") {
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return false;
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}
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const i = P >>> 0;
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if (i === 2 ** 32 - 1) {
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return false;
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}
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const s = `${i}`;
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if (P !== s) {
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return false;
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}
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return true;
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}
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const arrayBufferByteLengthGetter =
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Object.getOwnPropertyDescriptor(ArrayBuffer.prototype, "byteLength").get;
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function isArrayBuffer(value) {
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try {
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arrayBufferByteLengthGetter.call(value);
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return true;
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} catch {
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return false;
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}
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}
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const sharedArrayBufferByteLengthGetter =
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Object.getOwnPropertyDescriptor(SharedArrayBuffer.prototype, "byteLength").get;
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function isSharedArrayBuffer(value) {
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try {
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sharedArrayBufferByteLengthGetter.call(value);
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return true;
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} catch {
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return false;
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}
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}
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function iteratorResult([key, value], kind) {
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let result;
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switch (kind) {
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case "key":
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result = key;
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break;
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case "value":
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result = value;
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break;
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case "key+value":
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result = [key, value];
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break;
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}
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return { value: result, done: false };
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}
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function ordinarySetWithOwnDescriptor(target, property, value, receiver, ownDesc) {
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if (ownDesc === undefined) {
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const parent = Reflect.getPrototypeOf(target);
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if (parent !== null) {
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return Reflect.set(parent, property, value, receiver);
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}
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ownDesc = { writable: true, enumerable: true, configurable: true, value: undefined };
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}
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if (isDataDescriptor(ownDesc)) {
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if (!ownDesc.writable) {
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return false;
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}
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if (!isObject(receiver)) {
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return false;
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}
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const existingDesc = Reflect.getOwnPropertyDescriptor(receiver, property);
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if (existingDesc !== undefined) {
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if (isAccessorDescriptor(existingDesc)) {
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return false;
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}
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if (existingDesc.writable === false) {
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return false;
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}
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const valueDesc = { value };
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return Reflect.defineProperty(receiver, property, valueDesc);
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}
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return Reflect.defineProperty(
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receiver,
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property,
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{ value, writable: true, enumerable: true, configurable: true }
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);
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}
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const setter = ownDesc.set;
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if (setter === undefined) {
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return false;
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}
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call(setter, receiver, value);
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return true;
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}
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function isDataDescriptor(desc) {
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return Object.hasOwn(desc, "value") || Object.hasOwn(desc, "writable");
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}
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function isAccessorDescriptor(desc) {
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return Object.hasOwn(desc, "get") || Object.hasOwn(desc, "set");
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}
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function getMethod(value, property, errPrefix = "The provided value") {
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const func = value[property];
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if (func === undefined || func === null) {
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return undefined;
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}
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if (typeof func !== "function") {
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throw new TypeError(`${errPrefix}'s ${property} property is not a function.`);
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}
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return func;
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}
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function createAsyncFromSyncIterator(syncIterator) {
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// Instead of re-implementing CreateAsyncFromSyncIterator and %AsyncFromSyncIteratorPrototype%,
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// we use yield* inside an async generator function to achieve the same result.
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// Wrap the sync iterator inside a sync iterable, so we can use it with yield*.
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const syncIterable = {
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[Symbol.iterator]: () => syncIterator
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};
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// Create an async generator function and immediately invoke it.
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const asyncIterator = (async function* () {
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return yield* syncIterable;
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})();
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// Return as an async iterator record.
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return asyncIterator;
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}
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function convertAsyncSequence(object, itemConverter, errPrefix = "The provided value") {
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if (!isObject(object)) {
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throw new TypeError(`${errPrefix} is not an object.`);
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}
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let method = getMethod(object, Symbol.asyncIterator, errPrefix);
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let type = "async";
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if (method === undefined) {
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method = getMethod(object, Symbol.iterator, errPrefix);
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if (method === undefined) {
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throw new TypeError(`${errPrefix} is not an async iterable object.`);
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}
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type = "sync";
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}
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return {
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object,
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method,
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type,
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// The wrapperSymbol ensures that if the async sequence is used as a return value,
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// that it exposes the original JavaScript value.
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// https://webidl.spec.whatwg.org/#js-async-iterable
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[wrapperSymbol]: object,
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// Implement the async iterator protocol, so users can iterate
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// the async sequence directly (e.g. with for await...of)
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// instead of needing to call a separate helper function to open the async sequence.
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// https://webidl.spec.whatwg.org/#async-sequence-open
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[Symbol.asyncIterator]() {
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return openAsyncSequence(object, method, type, itemConverter, `${errPrefix}'s iterator`);
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}
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};
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}
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function openAsyncSequence(object, method, type, itemConverter, errPrefix = "The provided value") {
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let iterator = call(method, object);
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if (!isObject(iterator)) {
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throw new TypeError(`${errPrefix}'s method must return an object`);
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}
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if (type === "sync") {
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iterator = createAsyncFromSyncIterator(iterator);
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}
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const nextMethod = iterator.next;
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return {
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async next() {
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const nextResult = await call(nextMethod, iterator);
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if (!isObject(nextResult)) {
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throw new TypeError(`${errPrefix}'s next method must return an object`);
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}
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const { done, value } = nextResult;
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if (done) {
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return { done: true, value: undefined };
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}
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return { done: false, value: itemConverter(value) };
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},
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async return(reason) {
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const returnMethod = getMethod(iterator, "return", errPrefix);
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if (returnMethod === undefined) {
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return { done: true, value: undefined };
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}
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const returnResult = await call(returnMethod, iterator, reason);
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if (!isObject(returnResult)) {
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throw new TypeError(`${errPrefix}'s return method must return an object`);
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}
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return { done: true, value: undefined };
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},
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[Symbol.asyncIterator]() {
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return this;
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}
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};
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}
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const supportsPropertyIndex = Symbol("supports property index");
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const supportedPropertyIndices = Symbol("supported property indices");
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const supportsPropertyName = Symbol("supports property name");
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const supportedPropertyNames = Symbol("supported property names");
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const indexedGet = Symbol("indexed property get");
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const indexedSetNew = Symbol("indexed property set new");
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const indexedSetExisting = Symbol("indexed property set existing");
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const namedGet = Symbol("named property get");
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const namedSetNew = Symbol("named property set new");
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const namedSetExisting = Symbol("named property set existing");
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const namedDelete = Symbol("named property delete");
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const asyncIteratorNext = Symbol("async iterator get the next iteration result");
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const asyncIteratorReturn = Symbol("async iterator return steps");
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const asyncIteratorInit = Symbol("async iterator initialization steps");
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const asyncIteratorEOI = Symbol("async iterator end of iteration");
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module.exports = exports = {
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isObject,
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define,
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newObjectInRealm,
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wrapperSymbol,
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implSymbol,
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getSameObject,
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ctorRegistrySymbol,
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initCtorRegistry,
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wrapperForImpl,
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implForWrapper,
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tryWrapperForImpl,
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tryImplForWrapper,
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iterInternalSymbol,
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isArrayBuffer,
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isSharedArrayBuffer,
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isArrayIndexPropName,
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getMethod,
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convertAsyncSequence,
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supportsPropertyIndex,
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supportedPropertyIndices,
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supportsPropertyName,
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supportedPropertyNames,
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indexedGet,
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indexedSetNew,
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indexedSetExisting,
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namedGet,
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namedSetNew,
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namedSetExisting,
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namedDelete,
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asyncIteratorNext,
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asyncIteratorReturn,
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asyncIteratorInit,
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asyncIteratorEOI,
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iteratorResult,
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ordinarySetWithOwnDescriptor
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};
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