DefineOwnProperty.jsā¢1.49 kB
'use strict';
var hasPropertyDescriptors = require('has-property-descriptors');
var $defineProperty = require('es-define-property');
var hasArrayLengthDefineBug = hasPropertyDescriptors.hasArrayLengthDefineBug();
// eslint-disable-next-line global-require
var isArray = hasArrayLengthDefineBug && require('../helpers/IsArray');
var callBound = require('call-bound');
var $isEnumerable = callBound('Object.prototype.propertyIsEnumerable');
// eslint-disable-next-line max-params
module.exports = function DefineOwnProperty(IsDataDescriptor, SameValue, FromPropertyDescriptor, O, P, desc) {
if (!$defineProperty) {
if (!IsDataDescriptor(desc)) {
// ES3 does not support getters/setters
return false;
}
if (!desc['[[Configurable]]'] || !desc['[[Writable]]']) {
return false;
}
// fallback for ES3
if (P in O && $isEnumerable(O, P) !== !!desc['[[Enumerable]]']) {
// a non-enumerable existing property
return false;
}
// property does not exist at all, or exists but is enumerable
var V = desc['[[Value]]'];
// eslint-disable-next-line no-param-reassign
O[P] = V; // will use [[Define]]
return SameValue(O[P], V);
}
if (
hasArrayLengthDefineBug
&& P === 'length'
&& '[[Value]]' in desc
&& isArray(O)
&& O.length !== desc['[[Value]]']
) {
// eslint-disable-next-line no-param-reassign
O.length = desc['[[Value]]'];
return O.length === desc['[[Value]]'];
}
$defineProperty(O, P, FromPropertyDescriptor(desc));
return true;
};