blob: fe626e1834fb3e5d391609c15e93d45994d8c49c [file] [log] [blame]
Tim van der Lippebc3a0b72021-11-08 15:22:371'use strict';
2
3var GetIntrinsic = require('../GetIntrinsic.js');
4
5var $construct = GetIntrinsic('%Reflect.construct%', true);
6
7var DefinePropertyOrThrow = require('./DefinePropertyOrThrow');
8try {
9 DefinePropertyOrThrow({}, '', { '[[Get]]': function () {} });
10} catch (e) {
11 // Accessor properties aren't supported
12 DefinePropertyOrThrow = null;
13}
14
15// https://ecma-international.org/ecma-262/6.0/#sec-isconstructor
16
17if (DefinePropertyOrThrow && $construct) {
18 var isConstructorMarker = {};
19 var badArrayLike = {};
20 DefinePropertyOrThrow(badArrayLike, 'length', {
21 '[[Get]]': function () {
22 throw isConstructorMarker;
23 },
24 '[[Enumerable]]': true
25 });
26
27 module.exports = function IsConstructor(argument) {
28 try {
29 // `Reflect.construct` invokes `IsConstructor(target)` before `Get(args, 'length')`:
30 $construct(argument, badArrayLike);
31 } catch (err) {
32 return err === isConstructorMarker;
33 }
34 };
35} else {
36 module.exports = function IsConstructor(argument) {
37 // unfortunately there's no way to truly check this without try/catch `new argument` in old environments
38 return typeof argument === 'function' && !!argument.prototype;
39 };
40}