ArraySpeciesCreate.js

'use strict';

var GetIntrinsic = require('get-intrinsic');

var $species = GetIntrinsic('%Symbol.species%', true);
var $TypeError = GetIntrinsic('%TypeError%');

var ArrayCreate = require('./ArrayCreate');
var Get = require('./Get');
var IsArray = require('./IsArray');
var IsConstructor = require('./IsConstructor');
var Type = require('./Type');

var isInteger = require('../helpers/isInteger');

// https://262.ecma-international.org/12.0/#sec-arrayspeciescreate

module.exports = function ArraySpeciesCreate(originalArray, length) {
	if (!isInteger(length) || length < 0) {
		throw new $TypeError('Assertion failed: length must be an integer >= 0');
	}

	var isArray = IsArray(originalArray);
	if (!isArray) {
		return ArrayCreate(length);
	}

	var C = Get(originalArray, 'constructor');
	// TODO: figure out how to make a cross-realm normal Array, a same-realm Array
	// if (IsConstructor(C)) {
	// 	if C is another realm's Array, C = undefined
	// 	Object.getPrototypeOf(Object.getPrototypeOf(Object.getPrototypeOf(Array))) === null ?
	// }
	if ($species && Type(C) === 'Object') {
		C = Get(C, $species);
		if (C === null) {
			C = void 0;
		}
	}

	if (typeof C === 'undefined') {
		return ArrayCreate(length);
	}
	if (!IsConstructor(C)) {
		throw new $TypeError('C must be a constructor');
	}
	return new C(length); // Construct(C, length);
};