Constnium/node_modules/es-abstract/2020/IsConstructor.js
2022-06-23 02:27:43 +02:00

40 lines
1.1 KiB
JavaScript

'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://ecma-international.org/ecma-262/6.0/#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;
};
}