'use strict'; var GetIntrinsic = require('../GetIntrinsic.js'); var $construct = GetIntrinsic('%Reflect.construct%', true); var DefinePropertyOrThrow = require('./DefinePropertyOrThrow'); try { DefinePropertyOrThrow({}, '', { '[[Get]]': function () {} }); } catch (e) { // Accessor properties aren't supported DefinePropertyOrThrow = null; } // https://262.ecma-international.org/6.0/#sec-isconstructor if (DefinePropertyOrThrow && $construct) { var isConstructorMarker = {}; var badArrayLike = {}; DefinePropertyOrThrow(badArrayLike, 'length', { '[[Get]]': function () { throw isConstructorMarker; }, '[[Enumerable]]': true }); module.exports = function IsConstructor(argument) { try { // `Reflect.construct` invokes `IsConstructor(target)` before `Get(args, 'length')`: $construct(argument, badArrayLike); } catch (err) { return err === isConstructorMarker; } }; } else { module.exports = function IsConstructor(argument) { // unfortunately there's no way to truly check this without try/catch `new argument` in old environments return typeof argument === 'function' && !!argument.prototype; }; }