var $ = require('../internals/export'); var isObject = require('../internals/is-object'); var onFreeze = require('../internals/internal-metadata').onFreeze; var FREEZING = require('../internals/freezing'); var fails = require('../internals/fails'); var nativePreventExtensions = Object.preventExtensions; var FAILS_ON_PRIMITIVES = fails(function () { nativePreventExtensions(1); }); // `Object.preventExtensions` method // https://tc39.github.io/ecma262/#sec-object.preventextensions $({ target: 'Object', stat: true, forced: FAILS_ON_PRIMITIVES, sham: !FREEZING }, { preventExtensions: function preventExtensions(it) { return nativePreventExtensions && isObject(it) ? nativePreventExtensions(onFreeze(it)) : it; } });