internet-programming/lab3/node_modules/has-property-descriptors/index.js

34 lines
817 B
JavaScript

'use strict';
var GetIntrinsic = require('get-intrinsic');
var $defineProperty = GetIntrinsic('%Object.defineProperty%', true);
var hasPropertyDescriptors = function hasPropertyDescriptors() {
if ($defineProperty) {
try {
$defineProperty({}, 'a', { value: 1 });
return true;
} catch (e) {
// IE 8 has a broken defineProperty
return false;
}
}
return false;
};
hasPropertyDescriptors.hasArrayLengthDefineBug = function hasArrayLengthDefineBug() {
// node v0.6 has a bug where array lengths can be Set but not Defined
if (!hasPropertyDescriptors()) {
return null;
}
try {
return $defineProperty([], 'length', { value: 1 }).length !== 1;
} catch (e) {
// In Firefox 4-22, defining length on an array throws an exception.
return true;
}
};
module.exports = hasPropertyDescriptors;