core-js/modules/es.reflect.set.js

'use strict';
var $ = require('../internals/export');
var call = require('../internals/function-call');
var anObject = require('../internals/an-object');
var isObject = require('../internals/is-object');
var isDataDescriptor = require('../internals/is-data-descriptor');
var fails = require('../internals/fails');
var definePropertyModule = require('../internals/object-define-property');
var getOwnPropertyDescriptorModule = require('../internals/object-get-own-property-descriptor');
var getPrototypeOf = require('../internals/object-get-prototype-of');
var createPropertyDescriptor = require('../internals/create-property-descriptor');

// `Reflect.set` method
// https://tc39.es/ecma262/#sec-reflect.set
function set(target, propertyKey, V /* , receiver */) {
  var receiver = arguments.length < 4 ? target : arguments[3];
  var ownDescriptor = getOwnPropertyDescriptorModule.f(anObject(target), propertyKey);
  var existingDescriptor, prototype, setter;
  if (!ownDescriptor) {
    if (isObject(prototype = getPrototypeOf(target))) {
      return set(prototype, propertyKey, V, receiver);
    }
    ownDescriptor = createPropertyDescriptor(0);
  }
  if (isDataDescriptor(ownDescriptor)) {
    if (ownDescriptor.writable === false || !isObject(receiver)) return false;
    if (existingDescriptor = getOwnPropertyDescriptorModule.f(receiver, propertyKey)) {
      if (existingDescriptor.get || existingDescriptor.set || existingDescriptor.writable === false) return false;
      existingDescriptor.value = V;
      definePropertyModule.f(receiver, propertyKey, existingDescriptor);
    } else definePropertyModule.f(receiver, propertyKey, createPropertyDescriptor(0, V));
  } else {
    setter = ownDescriptor.set;
    if (setter === undefined) return false;
    call(setter, receiver, V);
  } return true;
}

// MS Edge 17-18 Reflect.set allows setting the property to object
// with non-writable property on the prototype
var MS_EDGE_BUG = fails(function () {
  var Constructor = function () { /* empty */ };
  var object = definePropertyModule.f(new Constructor(), 'a', { configurable: true });
  // eslint-disable-next-line es/no-reflect -- required for testing
  return Reflect.set(Constructor.prototype, 'a', 1, object) !== false;
});

$({ target: 'Reflect', stat: true, forced: MS_EDGE_BUG }, {
  set: set
});