You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
41 lines
1.1 KiB
41 lines
1.1 KiB
4 years ago
|
'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;
|
||
|
|
};
|
||
|
|
}
|