get-anonymous-intrinsics.js

import {
  FERAL_FUNCTION,
  Float32Array,
  Map,
  Set,
  String,
  getOwnPropertyDescriptor,
  getPrototypeOf,
  iterateArray,
  iterateMap,
  iterateSet,
  iterateString,
  matchAllRegExp,
  matchAllSymbol,
  regexpPrototype,
} from './commons.js';
import { InertCompartment } from './compartment-shim.js';

/**
 * Object.getConstructorOf()
 * Helper function to improve readability, similar to Object.getPrototypeOf().
 *
 * @param {Object} obj
 */
function getConstructorOf(obj) {
  return getPrototypeOf(obj).constructor;
}

// getAnonymousIntrinsics uses a utility function to construct an arguments
// object, since it cannot have one of its own and also be a const export.
function makeArguments() {
  // eslint-disable-next-line prefer-rest-params
  return arguments;
}

/**
 * getAnonymousIntrinsics()
 * Get the intrinsics not otherwise reachable by named own property
 * traversal from the global object.
 *
 * @returns {Object}
 */
export const getAnonymousIntrinsics = () => {
  const InertFunction = FERAL_FUNCTION.prototype.constructor;

  // 9.2.4.1 %ThrowTypeError%

  const ThrowTypeError = getOwnPropertyDescriptor(makeArguments(), 'callee')
    .get;

  // 21.1.5.2 The %StringIteratorPrototype% Object

  // eslint-disable-next-line no-new-wrappers
  const StringIteratorObject = iterateString(new String());
  const StringIteratorPrototype = getPrototypeOf(StringIteratorObject);

  // 21.2.7.1 The %RegExpStringIteratorPrototype% Object
  const RegExpStringIterator =
    regexpPrototype[matchAllSymbol] && matchAllRegExp(/./);
  const RegExpStringIteratorPrototype =
    RegExpStringIterator && getPrototypeOf(RegExpStringIterator);

  // 22.1.5.2 The %ArrayIteratorPrototype% Object

  // eslint-disable-next-line no-array-constructor
  const ArrayIteratorObject = iterateArray([]);
  const ArrayIteratorPrototype = getPrototypeOf(ArrayIteratorObject);

  // 22.2.1 The %TypedArray% Intrinsic Object

  const TypedArray = getPrototypeOf(Float32Array);

  // 23.1.5.2 The %MapIteratorPrototype% Object

  const MapIteratorObject = iterateMap(new Map());
  const MapIteratorPrototype = getPrototypeOf(MapIteratorObject);

  // 23.2.5.2 The %SetIteratorPrototype% Object

  const SetIteratorObject = iterateSet(new Set());
  const SetIteratorPrototype = getPrototypeOf(SetIteratorObject);

  // 25.1.2 The %IteratorPrototype% Object

  const IteratorPrototype = getPrototypeOf(ArrayIteratorPrototype);

  // 25.2.1 The GeneratorFunction Constructor

  // eslint-disable-next-line no-empty-function
  function* GeneratorFunctionInstance() {}
  const GeneratorFunction = getConstructorOf(GeneratorFunctionInstance);

  // 25.2.3 Properties of the GeneratorFunction Prototype Object

  const Generator = GeneratorFunction.prototype;

  // 25.3.1 The AsyncGeneratorFunction Constructor

  // eslint-disable-next-line no-empty-function
  async function* AsyncGeneratorFunctionInstance() {}
  const AsyncGeneratorFunction = getConstructorOf(
    AsyncGeneratorFunctionInstance,
  );

  // 25.3.2.2 AsyncGeneratorFunction.prototype
  const AsyncGenerator = AsyncGeneratorFunction.prototype;
  // 25.5.1 Properties of the AsyncGenerator Prototype Object
  const AsyncGeneratorPrototype = AsyncGenerator.prototype;
  const AsyncIteratorPrototype = getPrototypeOf(AsyncGeneratorPrototype);

  // 25.7.1 The AsyncFunction Constructor

  // eslint-disable-next-line no-empty-function
  async function AsyncFunctionInstance() {}
  const AsyncFunction = getConstructorOf(AsyncFunctionInstance);

  const intrinsics = {
    '%InertFunction%': InertFunction,
    '%ArrayIteratorPrototype%': ArrayIteratorPrototype,
    '%InertAsyncFunction%': AsyncFunction,
    '%AsyncGenerator%': AsyncGenerator,
    '%InertAsyncGeneratorFunction%': AsyncGeneratorFunction,
    '%AsyncGeneratorPrototype%': AsyncGeneratorPrototype,
    '%AsyncIteratorPrototype%': AsyncIteratorPrototype,
    '%Generator%': Generator,
    '%InertGeneratorFunction%': GeneratorFunction,
    '%IteratorPrototype%': IteratorPrototype,
    '%MapIteratorPrototype%': MapIteratorPrototype,
    '%RegExpStringIteratorPrototype%': RegExpStringIteratorPrototype,
    '%SetIteratorPrototype%': SetIteratorPrototype,
    '%StringIteratorPrototype%': StringIteratorPrototype,
    '%ThrowTypeError%': ThrowTypeError,
    '%TypedArray%': TypedArray,
    '%InertCompartment%': InertCompartment,
  };

  return intrinsics;
};