core-js/modules/es6.reflect.is-extensible.js

Standard library

// 26.1.10 Reflect.isExtensible(target)
var $def          = require('./$.def')
  , anObject      = require('./$.an-object')
  , $isExtensible = Object.isExtensible;

$def($def.S, 'Reflect', {
  isExtensible: function isExtensible(target){
    anObject(target);
    return $isExtensible ? $isExtensible(target) : true;
  }
});