packages/core-js/modules/es.object.lookup-getter.js

'use strict';
var $ = require('../internals/export');
var DESCRIPTORS = require('../internals/descriptors');
var FORCED = require('../internals/object-prototype-accessors-forced');
var toObject = require('../internals/to-object');
var toPropertyKey = require('../internals/to-property-key');
var getPrototypeOf = require('../internals/object-get-prototype-of');
var getOwnPropertyDescriptor = require('../internals/object-get-own-property-descriptor').f;

// `Object.prototype.__lookupGetter__` method
// https://tc39.es/ecma262/#sec-object.prototype.__lookupGetter__
if (DESCRIPTORS) {
  $({ target: 'Object', proto: true, forced: FORCED }, {
    __lookupGetter__: function __lookupGetter__(P) {
      var O = toObject(this);
      var key = toPropertyKey(P);
      var desc;
      do {
        if (desc = getOwnPropertyDescriptor(O, key)) return desc.get;
      } while (O = getPrototypeOf(O));
    }
  });
}