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Last change
on this file was d565449, checked in by stefan toskovski <stefantoska84@…>, 4 weeks ago |
Update repo after prototype presentation
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File size:
1.1 KB
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1 | 'use strict';
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2 |
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3 | var GetIntrinsic = require('../GetIntrinsic.js');
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4 |
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5 | var $construct = GetIntrinsic('%Reflect.construct%', true);
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6 |
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7 | var DefinePropertyOrThrow = require('./DefinePropertyOrThrow');
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8 | try {
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9 | DefinePropertyOrThrow({}, '', { '[[Get]]': function () {} });
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10 | } catch (e) {
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11 | // Accessor properties aren't supported
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12 | DefinePropertyOrThrow = null;
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13 | }
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14 |
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15 | // https://262.ecma-international.org/6.0/#sec-isconstructor
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16 |
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17 | if (DefinePropertyOrThrow && $construct) {
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18 | var isConstructorMarker = {};
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19 | var badArrayLike = {};
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20 | DefinePropertyOrThrow(badArrayLike, 'length', {
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21 | '[[Get]]': function () {
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22 | throw isConstructorMarker;
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23 | },
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24 | '[[Enumerable]]': true
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25 | });
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26 |
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27 | module.exports = function IsConstructor(argument) {
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28 | try {
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29 | // `Reflect.construct` invokes `IsConstructor(target)` before `Get(args, 'length')`:
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30 | $construct(argument, badArrayLike);
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31 | } catch (err) {
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32 | return err === isConstructorMarker;
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33 | }
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34 | };
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35 | } else {
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36 | module.exports = function IsConstructor(argument) {
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37 | // unfortunately there's no way to truly check this without try/catch `new argument` in old environments
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38 | return typeof argument === 'function' && !!argument.prototype;
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39 | };
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40 | }
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