core-js/tests/unit-global/es.object.lookup-getter.js

import { DESCRIPTORS, STRICT } from '../helpers/constants.js';

if (DESCRIPTORS) {
  QUnit.test('Object#__lookupGetter__', assert => {
    const { __lookupGetter__ } = Object.prototype;
    const { create } = Object;
    assert.isFunction(__lookupGetter__);
    assert.arity(__lookupGetter__, 1);
    assert.name(__lookupGetter__, '__lookupGetter__');
    assert.looksNative(__lookupGetter__);
    assert.nonEnumerable(Object.prototype, '__lookupGetter__');
    assert.same({}.__lookupGetter__('key'), undefined, 'empty object');
    assert.same({ key: 42 }.__lookupGetter__('key'), undefined, 'data descriptor');
    const object = {};
    function getter() { /* empty */ }
    object.__defineGetter__('key', getter);
    assert.same(object.__lookupGetter__('key'), getter, 'own getter');
    assert.same(create(object).__lookupGetter__('key'), getter, 'proto getter');
    assert.same(create(object).__lookupGetter__('foo'), undefined, 'empty proto');
    if (STRICT) {
      assert.throws(() => __lookupGetter__.call(null, 1, () => { /* empty */ }), TypeError, 'Throws on null as `this`');
      assert.throws(() => __lookupGetter__.call(undefined, 1, () => { /* empty */ }), TypeError, 'Throws on undefined as `this`');
    }
  });
}